Organic Compound, Light-Emitting Element, Light-Emitting Device, Electronic Device, and Lighting Device

ABSTRACT

A furopyrazine derivative that is a novel organic compound is provided. The organic compound has a furopyrazine skeleton and is represented by General Formula (G1). 
     
       
         
         
             
             
         
       
     
     In General Formula (G1), Q represents oxygen or sulfur, Ar 1  represents a substituted or unsubstituted condensed aromatic ring, R 1  and R 2  independently represent hydrogen or a group having 1 to 100 total carbon atoms, and at least one of R 1  and R 2  has a hole-transport skeleton.

BACKGROUND OF THE INVENTION 1. Field of the Invention

One embodiment of the present invention relates to an organic compound,a light-emitting element, a light-emitting device, an electronic device,and a lighting device. Note that one embodiment of the present inventionis not limited to the above technical field. That is, one embodiment ofthe present invention relates to an object, a method, a manufacturingmethod, or a driving method. One embodiment of the present inventionrelates to a process, a machine, manufacture, or a composition ofmatter. Specific examples include a semiconductor device, a displaydevice, and a liquid crystal display device.

2. Description of the Related Art

A light-emitting element including an EL layer between a pair ofelectrodes (also referred to as an organic EL element) hascharacteristics such as thinness, light weight, high-speed response toinput signals, and low power consumption; thus, a display including sucha light-emitting element has attracted attention as a next-generationflat panel display.

In a light-emitting element, voltage application between a pair ofelectrodes causes, in an EL layer, recombination of electrons and holesinjected from the electrodes, which brings a light-emitting substance(organic compound) contained in the EL layer into an excited state.Light is emitted when the light-emitting substance returns to the groundstate from the excited state. The excited state can be a singlet excitedstate (S*) and a triplet excited state (T*). Light emission from asinglet excited state is referred to as fluorescence, and light emissionfrom a triplet excited state is referred to as phosphorescence. Thestatistical generation ratio thereof in the light-emitting element isconsidered to be S*:T*=1:3. Since the spectrum of light emitted from alight-emitting substance depends on the light-emitting substance, theuse of different types of organic compounds as light-emitting substancesmakes it possible to obtain light-emitting elements that exhibit variouscolors.

Various kinds of substances have been developed as organic compounds andsynthesis methods and the like of the substances have also beendeveloped. The organic compounds have a wide variety of uses anddevelopment fields. In the field of biochemistry, a method for easilysynthesizing a substance having a naphthofuropyrazine skeleton isreported (see Non-Patent Document 1, for example).

However, a novel substance containing, as a raw material, the substancehaving the naphthofuropyrazine skeleton has not been developed yet.

REFERENCE Non-Patent Document

-   [Non-Patent Document 1] K. Shiva Kumar, Raju Adepu, Ravikumar    Kapavarapu, D. Rambabu, G. Rama Krishna, C. Malla Reddy, K. Krishna    Priya, Kishore V. L. Parsa, and Manojit Pal, “AlCl₃ Induced    C-arylation/cyclization in a Single Pot: A New Route to Benzofuran    Fused N-heterocycles of Pharmacological Interest”, Tetrahedron    Letters, 2012, Vol. 53, pp. 1134-1138.

SUMMARY OF THE INVENTION

Thus, an object of one embodiment of the present invention is to providea novel organic compound containing, as a raw material, a substancehaving a furopyrazine skeleton (including naphthofuropyrazine). Anotherobject of one embodiment of the present invention is to provide afuropyrazine derivative that is a novel organic compound. Another objectof one embodiment of the present invention is to provide a novel organiccompound that can be used in a light-emitting element. Another object ofone embodiment of the present invention is to provide a novel organiccompound that can be used in an EL layer of a light-emitting element.Another object is to provide a highly reliable and novel light-emittingelement using a novel organic compound of one embodiment of the presentinvention. Another object is to provide a novel light-emitting device, anovel electronic device, or a novel lighting device. Note that thedescription of these objects does not disturb the existence of otherobjects. In one embodiment of the present invention, there is no need toachieve all the objects. Other objects will be apparent from and can bederived from the description of the specification, the drawings, theclaims, and the like.

One embodiment of the present invention is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Q represents oxygen or sulfur, Ar¹ represents asubstituted or unsubstituted condensed aromatic ring, R¹ and R²independently represent hydrogen or a group having 1 to 100 total carbonatoms, and at least one of R¹ and R² has a hole-transport skeleton.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Q represents oxygen or sulfur, Ar¹ representsany one of substituted or unsubstituted naphthalene, substituted orunsubstituted phenanthrene, and substituted or unsubstituted chrysene,R¹ and R² independently represent hydrogen or a group having 1 to 100total carbon atoms, and at least one of R¹ and R² has a hole-transportskeleton.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Q represents oxygen or sulfur, Ar¹ represents asubstituted or unsubstituted condensed aromatic ring, R¹ and R²independently represent hydrogen or a group having 1 to 100 total carbonatoms, and at least one of R¹ and R² is a group including a condensedring.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Q represents oxygen or sulfur, Ar¹ representsany one of substituted or unsubstituted naphthalene, substituted orunsubstituted phenanthrene, and substituted or unsubstituted chrysene,R¹ and R² independently represent hydrogen or a group having 1 to 100total carbon atoms, and at least one of R¹ and R² is a group including acondensed ring.

Note that in General Formula (G1), Ar¹ is represented by any one ofGeneral Formulae (t1) to (t3).

In General Formulae (t1) to (t3), R³ to R²⁴ independently represent anyone of hydrogen, a substituted or unsubstituted alkyl group having 1 to6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 7 carbon atoms, and a substituted or unsubstituted aryl group having6 to 30 carbon atoms. In addition, * represents a bonding portion inGeneral Formula (G1).

In the above embodiments, General Formula (G1) is any one of GeneralFormulae (G1-1) to (G1-4).

In General Formulae (G1-1) to (G1-4), Q represents oxygen or sulfur, R¹and R² independently represent hydrogen or a group having 1 to 100 totalcarbon atoms, at least one of R¹ and R² has a hole-transport skeleton,and R³ to R⁸ and R¹⁷ to R²⁴ independently represent any one of hydrogen,a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and a substituted or unsubstituted aryl group having 6 to 30carbon atoms.

In the above embodiments, the hole-transport skeleton is any one of asubstituted or unsubstituted diarylamino group, a substituted orunsubstituted condensed aromatic hydrocarbon ring, and a substituted orunsubstituted π-electron rich condensed heteroaromatic ring.

In some of the above embodiments, the condensed ring is any one of asubstituted or unsubstituted condensed aromatic hydrocarbon ring and asubstituted or unsubstituted π-electron rich condensed heteroaromaticring. Alternatively, the condensed ring is a substituted orunsubstituted condensed heteroaromatic ring having any one of adibenzothiophene skeleton, a dibenzofuran skeleton, and a carbazoleskeleton. Alternatively, the condensed ring is a substituted orunsubstituted condensed aromatic hydrocarbon ring having any one of anaphthalene skeleton, a fluorene skeleton, a triphenylene skeleton, anda phenanthrene skeleton.

In the above embodiments, R¹ and R² in General Formula (G1)independently represent hydrogen or a group having 1 to 100 total carbonatoms. At least one of R¹ and R² is a group represented by GeneralFormula (u1).

A¹-(α)_(n)-*  (u1)

In General Formula (u1), α represents a substituted or unsubstitutedarylene group having 6 to 25 carbon atoms, n represents an integer of 0to 4, and A¹ represents a substituted or unsubstituted aryl group having6 to 30 total carbon atoms or a substituted or unsubstituted heteroarylgroup having 3 to 30 total carbon atoms. In addition, * represents abonding portion in General Formula (G1).

In General Formula (u1), A¹ is any one of General Formulae (A¹-1) to(A¹-17).

In General Formulae (A¹-1) to (A¹-17), R^(A1) to R^(A11) independentlyrepresent any one of hydrogen, a substituted or unsubstituted alkylgroup having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 7 carbon atoms, and a substituted orunsubstituted aryl group having 6 to 30 carbon atoms.

In General Formula (u1), ac is any one of General Formulae (Ar-1) to(Ar-14).

In General Formulae (Ar-1) to (Ar-14), R^(B1) to R^(B14) independentlyrepresent any one of hydrogen, a substituted or unsubstituted alkylgroup having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 7 carbon atoms, and a substituted orunsubstituted aryl group having 6 to 30 carbon atoms.

Another embodiment of the present invention is an organic compoundrepresented by any one of Structural Formulae (100), (123), (125),(126), (133), (156), (208), (238), (239), (244), (245), and (246).

Note that the present invention also includes a novel organic compound(refer to Embodiment 1) serving as a raw material for synthesizing theaforementioned organic compound of one embodiment of the presentinvention. Another embodiment of the present invention is alight-emitting element including the aforementioned organic compound ofone embodiment of the present invention. The present invention alsoincludes a light-emitting element containing a guest material as well asthe aforementioned organic compound.

Another embodiment of the present invention is a light-emitting elementincluding the aforementioned organic compound of one embodiment of thepresent invention. Note that the present invention also includes alight-emitting element that uses the organic compound of one embodimentof the present invention for an EL layer between a pair of electrodesand a light-emitting layer in the EL layer. In addition to theaforementioned light-emitting elements, the present invention includes alight-emitting element including a layer (e.g., a cap layer) that is incontact with an electrode and contains an organic compound. In additionto the light-emitting element, a light-emitting device including atransistor, a substrate, and the like is also included in the scope ofthe invention. Furthermore, the scope of the invention includes, inaddition to the light-emitting device, an electronic device and alighting device that include a microphone, a camera, an operationbutton, an external connection portion, a housing, a cover, a support, aspeaker, and the like.

In addition, the scope of one embodiment of the present inventionincludes a light-emitting device including a light-emitting element, anda lighting device including the light-emitting device. Accordingly, thelight-emitting device in this specification refers to an image displaydevice or a light source (including a lighting device). In addition, thelight-emitting device includes the following in its category: a modulein which a connector such as a flexible printed circuit (FPC) or a tapecarrier package (TCP) is attached to a light-emitting device; a modulein which a printed wiring board is provided at the end of a TCP; and amodule in which an integrated circuit (IC) is directly mounted on alight-emitting element by a chip on glass (COG) method.

According to one embodiment of the present invention, a novel organiccompound containing, as a raw material, a substance having afuropyrazine skeleton (including naphthofuropyrazine) can be provided.According to another embodiment of the present invention, a furopyrazinederivative that is a novel organic compound can be provided. Accordingto another embodiment of the present invention, a novel organic compoundthat can be used in a light-emitting element can be provided. Accordingto another embodiment of the present invention, a novel organic compoundthat can be used in an EL layer of a light-emitting element can beprovided. According to another embodiment of the present invention, ahighly reliable and novel light-emitting element using a novel organiccompound of one embodiment of the present invention can be provided.Furthermore, a novel light-emitting device, a novel electronic device,or a novel lighting device can be provided. Note that the description ofthese effects does not disturb the existence of other effects. Oneembodiment of the present invention does not necessarily achieve all theeffects. Other effects will be apparent from and can be derived from thedescription of the specification, the drawings, the claims, and thelike.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIGS. 1A to 1E illustrate structures of light-emitting elements;

FIGS. 2A to 2C illustrate a light-emitting device;

FIGS. 3A and 3B illustrate a light-emitting device;

FIGS. 4A to 4G illustrate electronic devices;

FIGS. 5A to 5C illustrate an electronic device;

FIGS. 6A and 6B illustrate an automobile;

FIGS. 7A to 7D illustrate lighting devices;

FIG. 8 illustrates lighting devices;

FIG. 9 is a ¹H-NMR chart of an organic compound represented byStructural Formula (100);

FIGS. 10A and 10B show ultraviolet-visible absorption and emissionspectra of the organic compound represented by Structural Formula (100);

FIG. 11 illustrates a light-emitting element;

FIG. 12 shows current density-luminance characteristics of alight-emitting element 1 and a comparative light-emitting element 2;

FIG. 13 shows voltage-luminance characteristics of the light-emittingelement 1 and the comparative light-emitting element 2;

FIG. 14 shows luminance-current efficiency characteristics of thelight-emitting element 1 and the comparative light-emitting element 2;

FIG. 15 shows voltage-current characteristics of the light-emittingelement 1 and the comparative light-emitting element 2;

FIG. 16 shows emission spectra of the light-emitting element 1 and thecomparative light-emitting element 2;

FIG. 17 shows reliability of the light-emitting element 1 and thecomparative light-emitting element 2;

FIG. 18 shows current density-luminance characteristics of alight-emitting element 3;

FIG. 19 shows voltage-luminance characteristics of the light-emittingelement 3;

FIG. 20 shows luminance-current efficiency characteristics of thelight-emitting element 3;

FIG. 21 shows voltage-current characteristics of the light-emittingelement 3;

FIG. 22 shows an emission spectrum of the light-emitting element 3;

FIG. 23 shows reliability of the light-emitting element 3;

FIG. 24 shows current density-luminance characteristics of alight-emitting element 4;

FIG. 25 shows voltage-luminance characteristics of the light-emittingelement 4;

FIG. 26 shows luminance-current efficiency characteristics of thelight-emitting element 4;

FIG. 27 shows voltage-current characteristics of the light-emittingelement 4;

FIG. 28 shows an emission spectrum of the light-emitting element 4;

FIG. 29 shows reliability of the light-emitting element 4;

FIG. 30 shows current density-luminance characteristics of alight-emitting element 5;

FIG. 31 shows voltage-luminance characteristics of the light-emittingelement 5;

FIG. 32 shows luminance-current efficiency characteristics of thelight-emitting element 5;

FIG. 33 shows voltage-current characteristics of the light-emittingelement 5;

FIG. 34 shows an emission spectrum of the light-emitting element 5;

FIG. 35 shows reliability of the light-emitting element 5;

FIG. 36 is a ¹H-NMR chart of an organic compound represented byStructural Formula (123);

FIG. 37 is a ¹H-NMR chart of an organic compound represented byStructural Formula (125);

FIG. 38 is a ¹H-NMR chart of an organic compound represented byStructural Formula (126);

FIG. 39 is a ¹H-NMR chart of an organic compound represented byStructural Formula (133);

FIG. 40 is a ¹H-NMR chart of an organic compound represented byStructural Formula (156);

FIG. 41 is a ¹H-NMR chart of an organic compound represented byStructural Formula (208);

FIG. 42 is a ¹H-NMR chart of an organic compound represented byStructural Formula (238);

FIG. 43 is a ¹H-NMR chart of an organic compound represented byStructural Formula (239);

FIG. 44 is a ¹H-NMR chart of an organic compound represented byStructural Formula (244);

FIG. 45 is a ¹H-NMR chart of an organic compound represented byStructural Formula (245);

FIG. 46 is a ¹H-NMR chart of an organic compound represented byStructural Formula (246);

FIG. 47 shows current density-luminance characteristics of alight-emitting element 8;

FIG. 48 shows voltage-luminance characteristics of the light-emittingelement 8;

FIG. 49 shows luminance-current efficiency characteristics of thelight-emitting element 8;

FIG. 50 shows voltage-current characteristics of the light-emittingelement 8;

FIG. 51 shows an emission spectrum of the light-emitting element 8;

FIG. 52 shows reliability of the light-emitting element 8;

FIG. 53 shows current density-luminance characteristics of alight-emitting element 9;

FIG. 54 shows voltage-luminance characteristics of the light-emittingelement 9;

FIG. 55 shows luminance-current efficiency characteristics of thelight-emitting element 9;

FIG. 56 shows voltage-current characteristics of the light-emittingelement 9;

FIG. 57 shows an emission spectrum of the light-emitting element 9;

FIG. 58 shows reliability of the light-emitting element 9;

FIG. 59 shows current density-luminance characteristics oflight-emitting elements 10 to 15;

FIG. 60 shows voltage-luminance characteristics of the light-emittingelements 10 to 15;

FIG. 61 shows luminance-current efficiency characteristics of thelight-emitting elements 10 to 15;

FIG. 62 shows voltage-current characteristics of the light-emittingelements 10 to 15;

FIG. 63 shows emission spectra of the light-emitting elements 10 to 15;

FIG. 64 shows reliability of the light-emitting elements 10 to 15;

FIG. 65 shows current density-luminance characteristics of alight-emitting element 16 and a comparative light-emitting element 17;

FIG. 66 shows voltage-luminance characteristics of the light-emittingelement 16 and the comparative light-emitting element 17;

FIG. 67 shows luminance-current efficiency characteristics of thelight-emitting element 16 and the comparative light-emitting element 17;

FIG. 68 shows voltage-current characteristics of the light-emittingelement 16 and the comparative light-emitting element 17;

FIG. 69 shows emission spectra of the light-emitting element 16 and thecomparative light-emitting element 17; and

FIG. 70 shows reliability of the light-emitting element 16 and thecomparative light-emitting element 17.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention will be described in detail belowwith reference to the drawings. Note that the present invention is notlimited to the following description, and the modes and details of thepresent invention can be modified in various ways without departing fromthe spirit and scope of the present invention. Therefore, the presentinvention should not be construed as being limited to the description inthe following embodiments.

Note that the position, size, range, or the like of each componentillustrated in drawings and the like is not accurately represented insome cases for easy understanding. Therefore, the disclosed invention isnot necessarily limited to the position, size, range, or the likedisclosed in the drawings and the like.

In the description of modes of the present invention with reference tothe drawings in this specification and the like, the same components indifferent drawings are commonly denoted by the same reference numeral.

Embodiment 1

In this embodiment, an organic compound of one embodiment of the presentinvention will be described. Note that the organic compound of oneembodiment of the present invention has a naphthofuropyrazine skeletonand is represented by General Formula (G1).

Note that in General Formula (G1), Q represents oxygen or sulfur, Ar¹represents a substituted or unsubstituted condensed aromatic ring, R¹and R² independently represent hydrogen or a group having 1 to 100 totalcarbon atoms, and at least one of R¹ and R² has a hole-transportskeleton.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Q represents oxygen or sulfur, Ar¹ representsany one of substituted or unsubstituted naphthalene, substituted orunsubstituted phenanthrene, and substituted or unsubstituted chrysene,R¹ and R² independently represent hydrogen or a group having 1 to 100total carbon atoms, and at least one of R¹ and R² has a hole-transportskeleton.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Q represents oxygen or sulfur, Ar¹ represents asubstituted or unsubstituted condensed aromatic ring, R¹ and R²independently represent hydrogen or a group having 1 to 100 total carbonatoms, and at least one of R¹ and R² is a group including a condensedring.

Another embodiment of the present invention is an organic compoundrepresented by General Formula (G1).

In General Formula (G1), Q represents oxygen or sulfur, Ar¹ representsany one of substituted or unsubstituted naphthalene, substituted orunsubstituted phenanthrene, and substituted or unsubstituted chrysene,R¹ and R² independently represent hydrogen or a group having 1 to 100total carbon atoms, and at least one of R¹ and R² is a group including acondensed ring.

Note that in General Formula (G1), Ar¹ is represented by any one ofGeneral Formulae (t1) to (t3).

In General Formulae (t1) to (t3), R³ to R²⁴ independently represent anyone of hydrogen, a substituted or unsubstituted alkyl group having 1 to6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 7 carbon atoms, and a substituted or unsubstituted aryl group having6 to 30 carbon atoms. In addition, * represents a bonding portion inGeneral Formula (G1).

In the above embodiments, General Formula (G1) is any one of GeneralFormulae (G1-1) to (G1-4).

In General Formulae (G1-1) to (G1-4), Q represents oxygen or sulfur, R¹and R² independently represent hydrogen or a group having 1 to 100 totalcarbon atoms, at least one of R¹ and R² has a hole-transport skeleton,and R³ to R⁸ and R¹⁷ to R²⁴ independently represent any one of hydrogen,a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and a substituted or unsubstituted aryl group having 6 to 30carbon atoms.

In the above embodiments, the hole-transport skeleton included in atleast one of R¹ and R² is any one of a substituted or unsubstituteddiarylamino group, a substituted or unsubstituted condensed aromatichydrocarbon ring, and a substituted or unsubstituted π-electron richcondensed heteroaromatic ring. The condensed aromatic hydrocarbon ringpreferably includes any one of a naphthalene skeleton, a fluoreneskeleton, a triphenylene skeleton, and a phenanthrene skeleton. Theπ-electron rich condensed heteroaromatic ring is preferably a condensedheteroaromatic ring having any one of a dibenzothiophene skeleton, adibenzofuran skeleton, and a carbazole skeleton. The condensedheteroaromatic ring can be carbazole, dibenzothiophene, or dibenzofuran,or can be a condensed ring having a carbazole skeleton, adibenzothiophene skeleton, or a dibenzofuran skeleton in a ringstructure (i.e., a condensed ring in which a ring is condensed with acarbazole skeleton, a dibenzothiophene skeleton, or a dibenzofuranskeleton), such as benzocarbazole, dibenzocarbazole, indolocarbazole,benzindolocarbazole, dibenzindolocarbazole, benzindolobenzocarbazole,benzonaphthothiophene, or benzonaphthofuran.

In the above embodiments, the condensed ring included in at least one ofR¹ and R² is any one of a substituted or unsubstituted condensedaromatic hydrocarbon ring and a substituted or unsubstituted π-electronrich condensed heteroaromatic ring. The condensed ring is particularlypreferably a substituted or unsubstituted condensed aromatic hydrocarbonring having any one of a naphthalene skeleton, a fluorene skeleton, atriphenylene skeleton, and a phenanthrene skeleton. Alternatively, thecondensed ring is particularly preferably a substituted or unsubstitutedcondensed heteroaromatic ring having any one of a dibenzothiopheneskeleton, a dibenzofuran skeleton, and a carbazole skeleton. Thecondensed heteroaromatic ring can be carbazole, dibenzothiophene, ordibenzofuran, or can be a condensed ring having a carbazole skeleton, adibenzothiophene skeleton, or a dibenzofuran skeleton in a ringstructure (i.e., a condensed ring in which a ring is condensed with acarbazole skeleton, a dibenzothiophene skeleton, or a dibenzofuranskeleton), such as benzocarbazole, dibenzocarbazole, indolocarbazole,benzindolocarbazole, dibenzindolocarbazole, benzindolobenzocarbazole,benzonaphthothiophene, or benzonaphthofuran.

In the above embodiments, R¹ and R² in General Formula (G1)independently represent hydrogen or a group having 1 to 100 total carbonatoms. At least one of R¹ and R² is a group represented by GeneralFormula (u1).

A¹-(α)_(n)-*  (u1)

In General Formula (u1), α represents a substituted or unsubstitutedarylene group having 6 to 25 carbon atoms, n represents an integer of 0to 4, and A¹ represents a substituted or unsubstituted aryl group having6 to 30 total carbon atoms or a substituted or unsubstituted heteroarylgroup having 3 to 30 total carbon atoms.

In General Formula (u1), A¹ represents a substituted or unsubstitutedaryl group having 6 to 30 total carbon atoms or a substituted orunsubstituted heteroaryl group having 3 to 30 total carbon atoms.Specifically, A¹ is any one of General Formulae (A¹-1) to (A¹-17).

In General Formulae (A¹-1) to (A¹-17), R^(A1) to R^(A11) independentlyrepresent any one of hydrogen, a substituted or unsubstituted alkylgroup having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 7 carbon atoms, and a substituted orunsubstituted aryl group having 6 to 30 carbon atoms.

In General Formula (u1), α is any one of General Formulae (Ar-1) to(Ar-14).

In General Formulae (Ar-1) to (Ar-14), R^(B1) to R^(B14) independentlyrepresent any one of hydrogen, a substituted or unsubstituted alkylgroup having 1 to 6 carbon atoms, a substituted or unsubstitutedcycloalkyl group having 3 to 7 carbon atoms, and a substituted orunsubstituted aryl group having 6 to 30 carbon atoms.

Examples of the group having 1 to 100 total carbon atoms that isincluded in R¹ and R² in General Formula (G1) and General Formulae(G1-1) to (G1-4) include a substituted or unsubstituted alkyl grouphaving 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkylgroup having 3 to 7 carbon atoms, a substituted or unsubstituted arylgroup having 6 to 30 carbon atoms, and a substituted or unsubstitutedheteroaryl group having 3 to 30 carbon atoms. Note that at least one ofR¹ and R² has the hole-transport skeleton or the condensed ring.

Note that in the case where any of the substances listed below includesa substituent, examples of the substituent include an alkyl group having1 to 7 carbon atoms, such as a methyl group, an ethyl group, a propylgroup, an isopropyl group, a butyl group, an isobutyl group, a sec-butylgroup, a tert-butyl group, a pentyl group, or a hexyl group; acycloalkyl group having 5 to 7 carbon atoms, such as a cyclopentylgroup, a cyclohexyl group, a cycloheptyl group, or a8,9,10-trinorbornanyl group; and an aryl group having 6 to 12 carbonatoms, such as a phenyl group, a naphthyl group, or a biphenyl group.The substances are as follows: the substituted or unsubstitutedcondensed aromatic ring in General Formula (G1); the substituted orunsubstituted naphthalene, the substituted or unsubstitutedphenanthrene, and the substituted or unsubstituted chrysene in GeneralFormula (G1); the substituted or unsubstituted alkyl group having 1 to 6carbon atoms, the substituted or unsubstituted cycloalkyl group having 3to 7 carbon atoms, and the substituted or unsubstituted aryl grouphaving 6 to 30 carbon atoms in General Formulae (t1) to (t3); thesubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, thesubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and the substituted or unsubstituted aryl group having 6 to 30carbon atoms in General Formulae (G1-1) to (G1-4); the substituted orunsubstituted condensed aromatic hydrocarbon ring and the substituted orunsubstituted π-electron rich condensed heteroaromatic ring in GeneralFormula (G1); the substituted or unsubstituted arylene group having 6 to25 carbon atoms, the substituted or unsubstituted aryl group having 6 to30 total carbon atoms, and the substituted or unsubstituted heteroarylgroup having 3 to 30 total carbon atoms in General Formula (u1); thesubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, thesubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and the substituted or unsubstituted aryl group having 6 to 30carbon atoms in General Formulae (Ar-1) to (Ar-14); and the substitutedor unsubstituted alkyl group having 1 to 6 carbon atoms, the substitutedor unsubstituted cycloalkyl group having 3 to 7 carbon atoms, thesubstituted or unsubstituted aryl group having 6 to 30 carbon atoms, andthe substituted or unsubstituted heteroaryl group having 3 to 30 carbonatoms in the group having 1 to 100 total carbon atoms that is includedin R¹ and R² in General Formula (G1) and General Formulae (G1-1) to(G1-4).

Specific examples of the alkyl group having 1 to 6 carbon atoms inGeneral Formulae (t1) to (t3), General Formulae (G1-1) to (G1-4), andGeneral Formulae (A¹-1) to (A¹-17) include a methyl group, an ethylgroup, a propyl group, an isopropyl group, a butyl group, a sec-butylgroup, an isobutyl group, a tert-butyl group, a pentyl group, anisopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentylgroup, a hexyl group, an isohexyl group, a 3-methylpentyl group, a2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, a2,3-dimethylbutyl group, and an n-heptyl group.

Specific examples of the cycloalkyl group having 3 to 7 carbon atoms inGeneral Formulae (t1) to (t3), General Formulae (G1-1) to (G1-4), andGeneral Formulae (A¹-1) to (A¹-17) include a cyclopropyl group, acyclobutyl group, a cyclopentyl group, a cyclohexyl group, a1-methylcyclohexyl group, a 2,6-dimethylcyclohexyl group, a cycloheptylgroup, and a cyclooctyl group.

Specific examples of the aryl group having 6 to 30 carbon atoms inGeneral Formulae (t1) to (t3), General Formulae (G1-1) to (G1-4), andGeneral Formulae (A¹-1) to (A¹-17) include a phenyl group, an o-tolylgroup, an m-tolyl group, a p-tolyl group, a mesityl group, an o-biphenylgroup, an m-biphenyl group, a p-biphenyl group, a 1-naphthyl group, a2-naphthyl group, a fluorenyl group, a 9,9-dimethylfluorenyl group, aspirofluorenyl group, a phenanthrenyl group, an anthracenyl group, and afluoranthenyl group.

Specific examples of the aryl group having 6 to 30 carbon atoms in thegroup having 1 to 100 total carbon atoms that is included in R¹ and R²in General Formula (G1) and General Formulae (G1-1) to (G1-4) include aphenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, amesityl group, an o-biphenyl group, an m-biphenyl group, a p-biphenylgroup, a 1-naphthyl group, a 2-naphthyl group, a fluorenyl group, a9,9-dimethylfluorenyl group, a spirofluorenyl group, a phenanthrenylgroup, an anthracenyl group, and a fluoranthenyl group. In addition,specific examples of the heteroaryl group having 3 to 30 carbon atoms inthe group having 1 to 100 total carbon atoms that is included in R¹ andR² include monovalent groups such as carbazole, benzocarbazole,dibenzocarbazole, indolocarbazole, benzindolocarbazole,dibenzindolocarbazole, benzindolobenzocarbazole, dibenzothiophene,benzonaphthothiophene, dibenzofuran, and benzonaphthofuran.

Next, specific structural formulae of the aforementioned organiccompounds of embodiments of the present invention are shown below. Notethat the present invention is not limited to these formulae.

Note that the organic compounds represented by Structural Formulae (100)to (251) are examples of the organic compound represented by GeneralFormula (G1). The organic compound of one embodiment of the presentinvention is not limited thereto.

Next, an example of a method for synthesizing an organic compound of oneembodiment of the present invention represented by General Formula (G1′)will be described. Note that the organic compound represented by GeneralFormula (G1′) is a furopyrazine derivative condensed with a condensedaromatic ring or a thienopyrazine derivative condensed with a condensedaromatic ring. The organic compound represented by General Formula (G1′)is one embodiment of the organic compound represented by General Formula(G1).

In General Formula (G1′), Q represents oxygen or sulfur, R¹ represents agroup having 1 to 100 carbon atoms, R¹ represents a hole-transportskeleton, and Ar¹ represents a substituted or unsubstituted condensedaromatic ring.

<<Method for Synthesizing Organic Compound Represented by GeneralFormula (G1′)>>

A variety of reactions can be used for the synthesis of the organiccompound represented by General Formula (G1′). The organic compoundrepresented by General Formula (G1′) can be synthesized by a simplemethod shown by synthesis schemes below, for example.

First, as shown in a scheme (A-1) below, a methyloxy group-substitutedor methylthio group-substituted aryl boronic acid (a1) is coupled withan amino group-and-halogen-substituted pyrazine derivative (a2) toobtain an intermediate (a3), and then the intermediate (a3) is reactedwith tert-butyl nitrite and cyclized to obtain a furopyrazine derivativecondensed with a condensed aromatic ring (a4) or a thienopyrazinederivative condensed with a condensed aromatic ring (a4). Note that whenY¹ in the pyrazine derivative (a4) is halogen, an intermediate (a5)obtained by coupling of the pyrazine derivative (a4) and a boronic acidof an aromatic ring containing halogen (Y³—B¹) can be used in thefollowing reaction, similarly to the pyrazine derivative (a4).

In the synthesis scheme (A-1), Q represents oxygen or sulfur, Ar¹represents a substituted or unsubstituted condensed aromatic ring, Y¹represents halogen or an aromatic ring containing halogen, the number ofY¹ is one or two, Y² represents halogen, Y³ represents an aromatic ringcontaining halogen, the number of Y³ is one or two, and B¹ represents aboronic acid, a boronic ester, a cyclic-triolborate salt, or the like.As the cyclic-triolborate salt, a lithium salt, a potassium salt, or asodium salt may be used.

The organic compounds represented by General Formulae (a4) and (a5) inthe synthesis scheme (A-1) are raw materials of the organic compound ofone embodiment of the present invention as shown in a synthesis scheme(A-2) below. Note that the organic compounds represented by GeneralFormulae (a4) and (a5) are novel organic compounds and included in oneembodiment of the present invention. Specific structural formulae of theorganic compounds represented by General Formulae (a4) and (a5) areshown below.

Note that the organic compounds represented by Structural Formulae (300)to (347) are examples of the organic compounds represented by GeneralFormulae (a4) and (a5). The organic compound of one embodiment of thepresent invention is not limited thereto.

Next, as shown in the scheme (A-2) below, the furopyrazine derivativecondensed with a condensed aromatic ring (a4) or the thienopyrazinederivative condensed with a condensed aromatic ring (a4) obtained by thescheme (A-1) is coupled with a boronic acid compound (b1) to obtain theorganic compound represented by General Formula (G1′).

In the synthesis scheme (A-2), Q represents oxygen or sulfur, R¹represents a group having 1 to 100 carbon atoms, R¹ has a hole-transportskeleton, Ar¹ represents a substituted or unsubstituted condensedaromatic ring, Y¹ represents one or two halogens, and B² represents aboronic acid, a boronic ester, a cyclic-triolborate salt, or the like.As the cyclic-triolborate salt, a lithium salt, a potassium salt, or asodium salt may be used.

Since various kinds of the methyloxy group-substituted or methylthiogroup-substituted aryl boronic acid (a1), the aminogroup-and-halogen-substituted pyrazine derivative (a2), and the boronicacid compound (b1) that are used in the synthesis schemes (A-1) and(A-2) are commercially available or can be synthesized, a great varietyof the furopyrazine derivative condensed with a condensed aromatic ringor the thienopyrazine derivative condensed with a condensed aromaticring that is represented by General Formula (G1′) can be synthesized.Thus, a feature of the organic compound of one embodiment of the presentinvention is the abundance of variations.

Described above are the furopyrazine derivative condensed with acondensed aromatic ring or the thienopyrazine derivative condensed witha condensed aromatic ring, which is one embodiment of the presentinvention, and an example of the synthesis method thereof. The presentinvention is not limited to the one synthesized by the method, and anyother synthesis methods may be employed.

In this embodiment, embodiments of the present invention have beendescribed. Other embodiments of the present invention are described inthe other embodiments. Note that embodiments of the present inventionare not limited thereto. In other words, since various embodiments ofthe invention are described in this embodiment and the otherembodiments, embodiments of the present invention are not limited toparticular embodiments.

The structures described in this embodiment can be used in appropriatecombination with any of the structures described in the otherembodiments.

Embodiment 2

In this embodiment, a light-emitting element including any of theorganic compounds described in Embodiment 1 is described with referenceto FIGS. 1A to 1E.

<<Basic Structure of Light-Emitting Element>>

First, a basic structure of a light-emitting element will be described.FIG. 1A illustrates a light-emitting element including, between a pairof electrodes, an EL layer having a light-emitting layer. Specifically,an EL layer 103 is provided between a first electrode 101 and a secondelectrode 102.

FIG. 1B illustrates a light-emitting element that has a stacked-layerstructure (tandem structure) in which a plurality of EL layers (two ELlayers 103 a and 103 b in FIG. 1B) are provided between a pair ofelectrodes and a charge-generation layer 104 is provided between the ELlayers. With the use of such a tandem light-emitting element, alight-emitting device which can be driven at low voltage with low powerconsumption can be obtained.

The charge-generation layer 104 has a function of injecting electronsinto one of the EL layers (103 a or 103 b) and injecting holes into theother of the EL layers (103 b or 103 a) when voltage is applied betweenthe first electrode 101 and the second electrode 102. Thus, when voltageis applied in FIG. 1B such that the potential of the first electrode 101is higher than that of the second electrode 102, the charge-generationlayer 104 injects electrons into the EL layer 103 a and injects holesinto the EL layer 103 b.

Note that in terms of light extraction efficiency, the charge-generationlayer 104 preferably has a property of transmitting visible light(specifically, the charge-generation layer 104 has a visible lighttransmittance of 40% or more). The charge-generation layer 104 functionseven when it has lower conductivity than the first electrode 101 or thesecond electrode 102.

FIG. 1C illustrates a stacked-layer structure of the EL layer 103 in thelight-emitting element of one embodiment of the present invention. Inthis case, the first electrode 101 is regarded as functioning as ananode. The EL layer 103 has a structure in which a hole-injection layer111, a hole-transport layer 112, a light-emitting layer 113, anelectron-transport layer 114, and an electron-injection layer 115 arestacked in this order over the first electrode 101. Even in the casewhere a plurality of EL layers are provided as in the tandem structureillustrated in FIG. 1B, the layers in each EL layer are sequentiallystacked from the anode side as described above. When the first electrode101 is a cathode and the second electrode 102 is an anode, the stackingorder is reversed.

The light-emitting layer 113 included in the EL layers (103, 103 a, and103 b) contains an appropriate combination of a light-emitting substanceand a plurality of substances, so that fluorescence or phosphorescenceof a desired emission color can be obtained. The light-emitting layer113 may have a stacked-layer structure having different emission colors.In that case, the light-emitting substance and other substances aredifferent between the stacked light-emitting layers. Alternatively, theplurality of EL layers (103 a and 103 b) in FIG. 1B may exhibit theirrespective emission colors. Also in that case, the light-emittingsubstance and other substances are different between the light-emittinglayers.

The light-emitting element of one embodiment of the present inventioncan have a micro optical resonator (microcavity) structure when, forexample, the first electrode 101 is a reflective electrode and thesecond electrode 102 is a transflective electrode in FIG. 1C. Thus,light emission from the light-emitting layer 113 in the EL layer 103 canbe resonated between the electrodes and light emission obtained throughthe second electrode 102 can be intensified.

Note that when the first electrode 101 of the light-emitting element isa reflective electrode in which a reflective conductive material and alight-transmitting conductive material (transparent conductive film) arestacked, optical adjustment can be performed by controlling thethickness of the transparent conductive film. Specifically, when thewavelength of light obtained from the light-emitting layer 113 is λ, thedistance between the first electrode 101 and the second electrode 102 ispreferably adjusted to around mλ/2 (m is a natural number).

To amplify desired light (wavelength: λ) obtained from thelight-emitting layer 113, the optical path length from the firstelectrode 101 to a region where the desired light is obtained in thelight-emitting layer 113 (light-emitting region) and the optical pathlength from the second electrode 102 to the region where the desiredlight is obtained in the light-emitting layer 113 (light-emittingregion) are preferably adjusted to around (2m′+1)λ/4 (m′ is a naturalnumber). Here, the light-emitting region means a region where holes andelectrons are recombined in the light-emitting layer 113.

By such optical adjustment, the spectrum of specific monochromatic lightobtained from the light-emitting layer 113 can be narrowed and lightemission with high color purity can be obtained.

In that case, the optical path length between the first electrode 101and the second electrode 102 is, to be exact, the total thickness from areflective region in the first electrode 101 to a reflective region inthe second electrode 102. However, it is difficult to preciselydetermine the reflective regions in the first electrode 101 and thesecond electrode 102; thus, it is assumed that the above effect can besufficiently obtained wherever the reflective regions may be set in thefirst electrode 101 and the second electrode 102. Furthermore, theoptical path length between the first electrode 101 and thelight-emitting layer emitting the desired light is, to be exact, theoptical path length between the reflective region in the first electrode101 and the light-emitting region in the light-emitting layer emittingthe desired light. However, it is difficult to precisely determine thereflective region in the first electrode 101 and the light-emittingregion in the light-emitting layer emitting the desired light; thus, itis assumed that the above effect can be sufficiently obtained whereverthe reflective region and the light-emitting region may be set in thefirst electrode 101 and the light-emitting layer emitting the desiredlight.

The light-emitting element in FIG. 1C has a microcavity structure, sothat light (monochromatic light) with different wavelengths can beextracted even if the same EL layer is used. Thus, separate coloring forobtaining a plurality of emission colors (e.g., R, G, and B) is notnecessary. Therefore, high resolution can be easily achieved. Note thata combination with coloring layers (color filters) is also possible.Furthermore, emission intensity of light with a specific wavelength inthe front direction can be increased, whereby power consumption can bereduced.

A light-emitting element illustrated in FIG. 1E is an example of thelight-emitting element with the tandem structure illustrated in FIG. 1B,and includes three EL layers (103 a, 103 b, and 103 c) stacked withcharge-generation layers (104 a and 104 b) positioned therebetween, asillustrated in the figure. The three EL layers (103 a, 103 b, and 103 c)include respective light-emitting layers (113 a, 113 b, and 113 c) andthe emission colors of the light-emitting layers can be selected freely.For example, the light-emitting layer 113 a can be blue, thelight-emitting layer 113 b can be red, green, or yellow, and thelight-emitting layer 113 c can be blue. For another example, thelight-emitting layer 113 a can be red, the light-emitting layer 113 bcan be blue, green, or yellow, and the light-emitting layer 113 c can bered.

In the light-emitting element of one embodiment of the presentinvention, at least one of the first electrode 101 and the secondelectrode 102 is a light-transmitting electrode (e.g., a transparentelectrode or a transflective electrode). In the case where thelight-transmitting electrode is a transparent electrode, the transparentelectrode has a visible light transmittance of higher than or equal to40%. In the case where the light-transmitting electrode is atransflective electrode, the transflective electrode has a visible lightreflectance of higher than or equal to 20% and lower than or equal to80%, and preferably higher than or equal to 40% and lower than or equalto 70%. These electrodes preferably have a resistivity of 1×10⁻² Ωcm orless.

Furthermore, when one of the first electrode 101 and the secondelectrode 102 is a reflective electrode in the light-emitting element ofone embodiment of the present invention, the visible light reflectanceof the reflective electrode is higher than or equal to 40% and lowerthan or equal to 100%, and preferably higher than or equal to 70% andlower than or equal to 100%. This electrode preferably has a resistivityof 1×10⁻² Ωcm or less.

<<Specific Structure and Fabrication Method of Light-Emitting Element>>

Specific structures and fabrication methods of light-emitting elementsof embodiments of the present invention will be described with referenceto FIGS. 1A to 1E. Here, a light-emitting element having the tandemstructure in FIG. 1B and a microcavity structure will be described withreference to FIG. 1D. In the light-emitting element in FIG. 1D having amicrocavity structure, the first electrode 101 is formed as a reflectiveelectrode and the second electrode 102 is formed as a transflectiveelectrode. Thus, a single-layer structure or a stacked-layer structurecan be formed using one or more kinds of desired electrode materials.Note that the second electrode 102 is formed after formation of the ELlayer 103 b, with the use of a material selected as described above. Forfabrication of these electrodes, a sputtering method or a vacuumevaporation method can be used.

<First Electrode and Second Electrode>

As materials used for the first electrode 101 and the second electrode102, any of the following materials can be used in an appropriatecombination as long as the functions of the electrodes described abovecan be fulfilled. For example, a metal, an alloy, an electricallyconductive compound, a mixture of these, and the like can beappropriately used. Specifically, an In—Sn oxide (also referred to asITO), an In—Si—Sn oxide (also referred to as ITSO), an In—Zn oxide, anIn—W—Zn oxide, or the like can be used. In addition, it is possible touse a metal such as aluminum (Al), titanium (Ti), chromium (Cr),manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu),gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo),tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt),silver (Ag), yttrium (Y), or neodymium (Nd) or an alloy containing anappropriate combination of any of these metals. It is also possible touse a Group 1 element or a Group 2 element in the periodic table, whichis not described above (e.g., lithium (Li), cesium (Cs), calcium (Ca),or strontium (Sr)), a rare earth metal such as europium (Eu) orytterbium (Yb), an alloy containing an appropriate combination of any ofthese elements, graphene, or the like.

In the light-emitting element in FIG. 1D, when the first electrode 101is an anode, a hole-injection layer 111 a and a hole-transport layer 112a of the EL layer 103 a are sequentially stacked over the firstelectrode 101 by a vacuum evaporation method. After the EL layer 103 aand the charge-generation layer 104 are formed, a hole-injection layer111 b and a hole-transport layer 112 b of the EL layer 103 b aresequentially stacked over the charge-generation layer 104 in a similarmanner.

<Hole-Injection Layer and Hole-Transport Layer>

The hole-injection layers (111, 111 a, and 111 b) inject holes from thefirst electrode 101 that is an anode and the charge-generation layer(104) to the EL layers (103, 103 a, and 103 b) and each contain amaterial with a high hole-injection property.

As examples of the material with a high hole-injection property,transition metal oxides such as molybdenum oxide, vanadium oxide,ruthenium oxide, tungsten oxide, and manganese oxide can be given.Alternatively, it is possible to use any of the following materials:phthalocyanine-based compounds such as phthalocyanine (abbreviation:H₂Pc) and copper phthalocyanine (abbreviation: CuPc); aromatic aminecompounds such as4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation:DPAB) andN,N′-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(abbreviation: DNTPD); high molecular compounds such aspoly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid)(abbreviation: PEDOT/PSS); and the like.

Alternatively, as the material with a high hole-injection property, acomposite material containing a hole-transport material and an acceptormaterial (an electron-accepting material) can also be used. In thatcase, the acceptor material extracts electrons from the hole-transportmaterial, so that holes are generated in the hole-injection layers (111,111 a, and 1 b) and the holes are injected into the light-emittinglayers (113, 113 a, and 113 b) through the hole-transport layers (112,112 a, and 112 b). Note that each of the hole-injection layers (111, 111a, and 111 b) may be formed to have a single-layer structure using acomposite material containing a hole-transport material and an acceptormaterial (electron-accepting material), or a stacked-layer structure inwhich a layer including a hole-transport material and a layer includingan acceptor material (electron-accepting material) are stacked.

The hole-transport layers (112, 112 a, and 112 b) transport the holes,which are injected from the first electrode 101 and thecharge-generation layer (104) by the hole-injection layers (111, 111 a,and 111 b), to the light-emitting layers (113, 113 a, and 113 b). Notethat the hole-transport layers (112, 112 a, and 112 b) each contain ahole-transport material. It is particularly preferable that the HOMOlevel of the hole-transport material included in the hole-transportlayers (112, 112 a, and 112 b) be the same as or close to that of thehole-injection layers (111, 111 a, and 111 b).

Examples of the acceptor material used for the hole-injection layers(111, 111 a, and 111 b) include an oxide of a metal belonging to any ofGroups 4 to 8 of the periodic table. Specifically, molybdenum oxide,vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungstenoxide, manganese oxide, and rhenium oxide can be given. Among these,molybdenum oxide is especially preferable since it is stable in the air,has a low hygroscopic property, and is easy to handle. Alternatively,organic acceptors such as a quinodimethane derivative, a chloranilderivative, and a hexaazatriphenylene derivative can be used.Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane(abbreviation: F₄-TCNQ), chloranil,2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation:HAT-CN), and the like can be used.

The hole-transport materials used for the hole-injection layers (111,111 a, and 111 b) and the hole-transport layers (112, 112 a, and 112 b)are preferably substances with a hole mobility of greater than or equalto 10⁻⁶ cm²Ns. Note that other substances may be used as long as thesubstances have a hole-transport property higher than anelectron-transport property.

Preferred hole-transport materials are π-electron rich heteroaromaticcompounds (e.g., carbazole derivatives and indole derivatives) andaromatic amine compounds, examples of which include compounds having anaromatic amine skeleton, such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB orα-NPD),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD),4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: BPAFLP), 4-phenyl-3′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: mBPAFLP),4-phenyl-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation:PCBA1BP), 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole(abbreviation: PCPPn),N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine(abbreviation: PCBiF),N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF),4,4′-diphenyl-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBBi1BP),4-(1-naphthyl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBANB),4,4′-di(1-naphthyl)-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBNBB),9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine(abbreviation: PCBAF),N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9′-bifluoren-2-amine(abbreviation: PCBASF), 4,4′,4″-tris(carbazol-9-yl)triphenylamine(abbreviation: TCTA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine(abbreviation: TDATA), and4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: MTDATA); compounds having a carbazole skeleton, such as1,3-bis(N-carbazolyl)benzene (abbreviation: mCP),4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP),3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP),3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP),3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1),3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2),3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene(abbreviation: TCPB), and9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA);compounds having a thiophene skeleton, such as4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation:DBT3P-II),2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene(abbreviation: DBTFLP-III), and4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene(abbreviation: DBTFLP-IV); and compounds having a furan skeleton, suchas 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation:DBF3P-II) and4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran(abbreviation: mmDBFFLBi-II).

A high molecular compound such as poly(N-vinylcarbazole) (abbreviation:PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA),poly[N-(4-{N-[4-(4-diphenylamino)phenyl]phenyl-N-phenylamino}phenyl)methacrylamide](abbreviation: PTPDMA), orpoly[N,N′-bis(4-butylphenyl)-N,N′-bis(phenyl)benzidine] (abbreviation:Poly-TPD) can also be used.

Note that the hole-transport material is not limited to the aboveexamples and may be one of or a combination of various known materialswhen used for the hole-injection layers (111, 111 a, and 111 b) and thehole-transport layers (112, 112 a, and 112 b). Note that thehole-transport layers (112, 112 a, and 112 b) may each be formed of aplurality of layers. That is, for example, the hole-transport layers mayeach have a stacked-layer structure of a first hole-transport layer anda second hole-transport layer.

In the light-emitting element in FIG. 1D, the light-emitting layer 113 ais formed over the hole-transport layer 112 a of the EL layer 103 a by avacuum evaporation method. After the EL layer 103 a and thecharge-generation layer 104 are formed, the light-emitting layer 113 bis formed over the hole-transport layer 112 b of the EL layer 103 b by avacuum evaporation method.

<Light-Emitting Layer>

The light-emitting layers (113, 113 a, 113 b, and 113 c) each contain alight-emitting substance. Note that as the light-emitting substance, asubstance whose emission color is blue, violet, bluish violet, green,yellowish green, yellow, orange, red, or the like is appropriately used.When the plurality of light-emitting layers (113 a, 113 b, and 113 c)are formed using different light-emitting substances, different emissioncolors can be exhibited (for example, complementary emission colors arecombined to achieve white light emission). Furthermore, a stacked-layerstructure in which one light-emitting layer contains two or more kindsof light-emitting substances may be employed.

The light-emitting layers (113, 113 a, 113 b, and 113 c) may eachcontain one or more kinds of organic compounds (a host material and anassist material) in addition to a light-emitting substance (guestmaterial). As the one or more kinds of organic compounds, the organiccompounds of embodiments of the present invention described inEmbodiment 1 or one or both of the hole-transport material and theelectron-transport material described in this embodiment can be used.

As the light-emitting substance that can be used for the light-emittinglayers (113, 113 a, 113 b, and 113 c), a light-emitting substance thatconverts singlet excitation energy into light emission in the visiblelight range or a light-emitting substance that converts tripletexcitation energy into light emission in the visible light range can beused.

Examples of other light-emitting substances are given below.

As an example of the light-emitting substance that converts singletexcitation energy into light emission, a substance that emitsfluorescence (fluorescent material) can be given. Examples of thesubstance that emits fluorescence include a pyrene derivative, ananthracene derivative, a triphenylene derivative, a fluorene derivative,a carbazole derivative, a dibenzothiophene derivative, a dibenzofuranderivative, a dibenzoquinoxaline derivative, a quinoxaline derivative, apyridine derivative, a pyrimidine derivative, a phenanthrene derivative,and a naphthalene derivative. A pyrene derivative is particularlypreferable because it has a high emission quantum yield. Specificexamples of the pyrene derivative includeN,N′-bis(3-methylphenyl)-N,N′-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine(abbreviation: 1,6mMemFLPAPrn),N,N′-diphenyl-N,N′-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine(abbreviation: 1,6FLPAPrn),N,N′-bis(dibenzofuran-2-yl)-N,N′-diphenylpyrene-1,6-diamine(abbreviation: 1,6FrAPrn),N,N′-bis(dibenzothiophen-2-yl)-N,N′-diphenylpyrene-1,6-diamine(abbreviation: 1,6ThAPm),N,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine](abbreviation:1,6BnfAPrn),N,N′-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation:1,6BnfAPm-02), andN,N′-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine](abbreviation:1,6BnfAPrn-03).

In addition, it is possible to use5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2′-bipyridine (abbreviation:PAP2BPy), 5,6-bis[4′-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2′-bipyridine(abbreviation: PAPP2BPy),N,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenylstilbene-4,4′-diamine(abbreviation: YGA2S),4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine(abbreviation: YGAPA),4-(9H-carbazol-9-yl)-4′-(9,10-diphenyl-2-anthryl)triphenylamine(abbreviation: 2YGAPPA),N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: PCAPA),4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBAPA),4-[4-(10-phenyl-9-anthryl)phenyl]-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra(tert-butyl)perylene(abbreviation: TBP),N,N′-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N′,N′-triphenyl-1,4-phenylenediamine](abbreviation: DPABPA),N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: 2PCAPPA),N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N′,N′-triphenyl-1,4-phenylenediamine(abbreviation: 2DPAPPA), or the like.

As examples of a light-emitting substance that converts tripletexcitation energy into light emission, a substance that emitsphosphorescence (phosphorescent material) and a thermally activateddelayed fluorescence (TADF) material that exhibits thermally activateddelayed fluorescence can be given.

Examples of a phosphorescent material include an organometallic complex,a metal complex (platinum complex), and a rare earth metal complex.These substances exhibit the respective emission colors (emission peaks)and thus, any of them is appropriately selected according to need.

As examples of a phosphorescent material which emits blue or green lightand whose emission spectrum has a peak wavelength at greater than orequal to 450 nm and less than or equal to 570 nm, the followingsubstances can be given.

For example, organometallic complexes having a 4H-triazole skeleton,such astris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN²]phenyl-κC}iridium(III)(abbreviation: [Ir(mpptz-dmp)₃]),tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III)(abbreviation: [Ir(Mptz)₃]),tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(iPrptz-3b)₃]), andtris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(iPr5btz)₃]); organometallic complexes having a1H-triazole skeleton, such astris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III)(abbreviation: [Ir(Mptz1-mp)₃]) andtris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III)(abbreviation: [Ir(Prptz1-Me)₃]); organometallic complexes having animidazole skeleton, such asfac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III)(abbreviation: [Ir(iPrpmi)₃]) andtris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III)(abbreviation: [Ir(dmpimpt-Me)₃]); organometallic complexes in which aphenylpyridine derivative having an electron-withdrawing group is aligand, such asbis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviation: FIr6),bis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III) picolinate(abbreviation: FIrpic),bis{2-[3′,5′-bis(trifluoromethyl)phenyl]pyridinato-N,C^(2′)}iridium(III)picolinate (abbreviation: [Ir(CF₃ppy)₂(pic)]), andbis[2-(4′,6′-difluorophenyl)pyridinato-N,C^(2′)]iridium(III)acetylacetonate (abbreviation: FIr(acac)); and the like can be given.

As examples of a phosphorescent material which emits green or yellowlight and whose emission spectrum has a peak wavelength at greater thanor equal to 495 nm and less than or equal to 590 nm, the followingsubstances can be given.

For example, organometallic iridium complexes having a pyrimidineskeleton, such as tris(4-methyl-6-phenylpyrimidinato)iridium(III)(abbreviation: [Ir(mppm)₃]),tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation:[Ir(tBuppm)₃]),(acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III)(abbreviation: [Ir(mppm)₂(acac)]),(acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III)(abbreviation: [Ir(tBuppm)₂(acac)]),(acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III)(abbreviation: [Ir(nbppm)₂(acac)]),(acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III)(abbreviation: [Ir(mpmppm)₂(acac)]),(acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN³]phenyl-κC}iridium(Ill)(abbreviation: [Ir(dmppm-dmp)₂(acac)]), and(acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III)(abbreviation: [Ir(dppm)₂(acac)]); organometallic iridium complexeshaving a pyrazine skeleton, such as(acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III)(abbreviation: [Ir(mppr-Me)₂(acac)]) and(acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III)(abbreviation: [Ir(mppr-iPr)₂(acac)]); organometallic iridium complexeshaving a pyridine skeleton, such astris(2-phenylpyridinato-N,C^(2′))iridium(III) (abbreviation:[Ir(ppy)₃]), bis(2-phenylpyridinato-N,C^(2′))iridium(III)acetylacetonate (abbreviation: [Ir(ppy)₂(acac)]),bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation:[Ir(bzq)₂(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation:[Ir(bzq)₃]), tris(2-phenylquinolinato-N,C^(2′))iridium(III)(abbreviation: [Ir(pq)₃]), bis(2-phenylquinolinato-N,C^(2′))iridium(III)acetylacetonate (abbreviation: [Ir(pq)₂(acac)]),[2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III)(abbreviation: Ir(ppy)₂(4dppy)), andbis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC];organometallic complexes such asbis(2,4-diphenyl-1,3-oxazolato-N,C^(2′))iridium(III) acetylacetonate(abbreviation: [Ir(dpo)₂(acac)]),bis{2-[4′-(perfluorophenyl)phenyl]pyridinato-N,C^(2′)}iridium(III)acetylacetonate (abbreviation: [Ir(p-PF-ph)₂(acac)]), andbis(2-phenylbenzothiazolato-N,C^(2′))iridium(III) acetylacetonate(abbreviation: [Ir(bt)₂(acac)]); and rare earth metal complexes such astris(acetylacetonatomonophenanthroline)terbium(III) (abbreviation:[Tb(acac)₃(Phen)]) can be given.

As examples of a phosphorescent material which emits yellow or red lightand whose emission spectrum has a peak wavelength at greater than orequal to 570 nm and less than or equal to 750 nm, the followingsubstances can be given.

For example, organometallic complexes having a pyrimidine skeleton, suchas(diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III)(abbreviation: [Ir(5mdppm)₂(dibm)]),bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III)(abbreviation: [Ir(5mdppm)₂(dpm)]),bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III)(abbreviation: [Ir(d1npm)₂(dpm)]), andtris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation:[Ir(tBuppm)₃]); organometallic complexes having a pyrazine skeleton,such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III)(abbreviation: [Ir(tppr)₂(acac)]),bis(2,3,5-triphenylpyrazinatoXdipivaloylmethanato)iridium(III)(abbreviation: [Ir(tppr)₂(dpm)]),bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmdppr-P)₂(dibm)]),bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmdppr-dmCP)₂(dpm)]),(acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C^(2′)]iridium(III)(abbreviation: [Ir(mpq)₂(acac)]),(acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C^(2′))iridium(III)(abbreviation: [Ir(dpq)₂(acac)]),(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(abbreviation: [Ir(Fdpq)₂(acac)]), andbis{4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmdppr-m5CP)₂(dpm)]); organometallic complexes havinga pyridine skeleton, such astris(1-phenylisoquinolinato-N,C^(2′))iridium(III) (abbreviation:[Ir(piq)₃]), bis(1-phenylisoquinolinato-N,C^(2′))iridium(III)acetylacetonate (abbreviation: [Ir(piq)₂(acac)]), andbis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC](2,4-pentanedionato-κ²O,O′)iridium(III);platinum complexes such as2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II)(abbreviation: [PtOEP]); and rare earth metal complexes such astris(1,3-diphenyl-1,3-propanedionatoXmonophenanthroline)europium(III)(abbreviation: [Eu(DBM)₃(Phen)]) andtris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III)(abbreviation: [Eu(TTA)₃(Phen)]) can be given.

As the organic compounds (the host material and the assist material)used in the light-emitting layers (113, 113 a, 113 b, and 113 c), one ormore kinds of substances having a larger energy gap than thelight-emitting substance (the guest material) are used. In the casewhere a plurality of organic compounds are used for the light-emittinglayers (113, 113 a, 113 b, and 113 c), it is preferable to use compoundsthat form an exciplex in combination with a phosphorescentlight-emitting substance. With such a structure, light emission can beobtained by exciplex-triplet energy transfer (ExTET), which is energytransfer from an exciplex to a light-emitting substance. In that case,although any of various organic compounds can be used in an appropriatecombination, in order to form an exciplex efficiently, it isparticularly preferable to combine a compound that easily accepts holes(hole-transport material) and a compound that easily accepts electrons(electron-transport material). The organic compound of one embodiment ofthe present invention described in Embodiment 1 has a low LUMO level andthus is suitable for the compound that easily accepts electrons.

When the light-emitting substance is a fluorescent material, it ispreferable to use, as the host material, an organic compound that has ahigh energy level in a singlet excited state and has a low energy levelin a triplet excited state. For example, an anthracene derivative or atetracene derivative is preferably used. Specific examples thereofinclude 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole(abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole(abbreviation: CzPA),7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole(abbreviation: cgDBCzPA),6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan(abbreviation: 2mBnfPPA),9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4′-yl}anthracene(abbreviation: FLPPA), 5,12-diphenyltetracene, and5,12-bis(biphenyl-2-yl)tetracene.

In the case where the light-emitting substance is a phosphorescentmaterial, an organic compound having triplet excitation energy (energydifference between a ground state and a triplet excited state) which ishigher than that of the light-emitting substance is preferably selectedas the host material. The organic compound of one embodiment of thepresent invention described in Embodiment 1 has a stable triplet excitedstate and thus is particularly suitable for a host material in the casewhere the light-emitting substance is a phosphorescent material. Owingto the triplet excitation energy level, the organic compound isparticularly suitable when the phosphorescent material emits red light.Besides, a zinc- or aluminum-based metal complex, an oxadiazolederivative, a triazole derivative, a benzimidazole derivative, aquinoxaline derivative, a dibenzoquinoxaline derivative, adibenzothiophene derivative, a dibenzofuran derivative, a pyrimidinederivative, a triazine derivative, a pyridine derivative, a bipyridinederivative, a phenanthroline derivative, an aromatic amine, a carbazolederivative, or the like can be used as the host material.

More specifically, any of the following hole-transport materials andelectron-transport materials can be used as the host material, forexample.

Examples of the host material having a high hole-transport propertyinclude aromatic amine compounds such asN,N′-di(p-tolyl)-N,N′-diphenyl-p-phenylenediamine (abbreviation:DTDPPA), 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl(abbreviation: DPAB),N,N′-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine(abbreviation: DNTPD), and1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene(abbreviation: DPA3B).

Carbazole derivatives such as3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzDPA1),3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzDPA2),3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole(abbreviation: PCzTPN2),3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA1),3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole(abbreviation: PCzPCA2), and3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole(abbreviation: PCzPCN1) are also given. Other examples of the carbazolederivative include 4,4′-di(N-carbazolyl)biphenyl (abbreviation: CBP),1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene.

Examples of the host material having a high hole-transport propertyinclude aromatic amine compounds such as4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB orα-NPD),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(abbreviation: TPD), 4,4′,4″-tris(carbazol-9-yl)triphenylamine(abbreviation: TCTA),4,4′,4″-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation:1-TNATA), 4,4′,4″-tris(N,N-diphenylamino)triphenylamine (abbreviation:TDATA), 4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine(abbreviation: m-MTDATA),4,4′-bis[N-(spiro-9,9′-bifluoren-2-yl)-N-phenylamino]biphenyl(abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: BPAFLP), 4-phenyl-3′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: mBPAFLP),N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N-phenyl-N′-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine(abbreviation: DFLADFL),N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine(abbreviation: DPNF),2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9′-bifluorene(abbreviation: DPASF),4-phenyl-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation:PCBA1BP), 4,4′-diphenyl-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBBi1BP),4-(I-naphthyl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBANB),4,4′-di(1-naphthyl)-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBNBB),4-phenylbiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation:PCA1BP),N,N′-bis(9-phenylcarbazol-3-yl)-N,N′-diphenylbenzene-1,3-diamine(abbreviation: PCA2B),N,N′,N″-triphenyl-N,N′,N″-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine(abbreviation: PCA3B),N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine(abbreviation: PCBBiF),N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF),9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine(abbreviation: PCBAF),N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9′-bifluoren-2-amine(abbreviation: PCBASF),2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9′-bifluorene(abbreviation: PCASF),2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9′-bifluorene(abbreviation: DPA2SF),N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation:YGA1BP), andN,N′-bis[4-(carbazol-9-yl)phenyl]-N,N′-diphenyl-9,9-dimethylfluorene-2,7-diamine(abbreviation: YGA2F). Other examples are carbazole compounds, thiophenecompounds, furan compounds, fluorene compounds, triphenylene compounds,phenanthrene compounds, and the like such as3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN),3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation:PCPPn), 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP),1,3-bis(N-carbazolyl)benzene (abbreviation: mCP),3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP),4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran(abbreviation: mmDBFFLBi-II),4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II),1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II),2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene(abbreviation: DBTFLP-III),4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene(abbreviation: DBTFLP-IV), and4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation:mDBTPTp-II).

Examples of the host material having a high electron-transport propertyinclude the organic compounds of embodiments of the present inventiondescribed in Embodiment 1 and a metal complex having a quinolineskeleton or a benzoquinoline skeleton, such astris(8-quinolinolato)aluminum(III) (abbreviation: Alq),tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq₃),bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq₂),bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III)(abbreviation: BAlq), or bis(8-quinolinolato)zinc(II) (abbreviation:Znq). Alternatively, a metal complex having an oxazole-based orthiazole-based ligand, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II)(abbreviation: ZnPBO) or bis[2-(2-benzothiazolyl)phenolato]zinc(II)(abbreviation: ZnBTZ) can be used. Other than such metal complexes, anyof the following can be used: oxadiazole derivatives such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene(abbreviation: OXD-7), and9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation:CO11); a triazole derivative such as3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole(abbreviation: TAZ); a compound having an imidazole skeleton (inparticular, a benzimidazole derivative) such as2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole)(abbreviation: TPBI) or2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole(abbreviation: mDBTBIm-II); a compound having an oxazole skeleton (inparticular, a benzoxazole derivative) such as4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs); aphenanthroline derivative such as bathophenanthroline (abbreviation:Bphen), bathocuproine (abbreviation: BCP), and2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation:NBphen); heterocyclic compounds having a diazine skeleton such as2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:2mDBTPDBq-II),2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II),2-[3′-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mCzBPDBq),2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline(abbreviation: 2CzPDBq-III),7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline(abbreviation: 6mDBTPDBq-II),4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation:4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine(abbreviation: 4,6mDBTP2Pm-II), and4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation:4,6mCzP2Pm); heterocyclic compounds having a triazine skeleton such as2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine(abbreviation: PCCzPTzn) and9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9′-phenyl-2,3′-bi-9H-carbazole(abbreviation: mPCCzPTzn-02); and heterocyclic compounds having apyridine skeleton such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine(abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene(abbreviation: TmPyPB). Further alternatively, a high molecular compoundsuch as poly(2,5-pyridinediyl) (abbreviation: PPy),poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation:PF-Py), orpoly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation: PF-BPy) can be used.

Examples of the host material include condensed polycyclic aromaticcompounds such as anthracene derivatives, phenanthrene derivatives,pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysenederivatives. Specific examples of the condensed polycyclic aromaticcompound include 9,10-diphenylanthracene (abbreviation: DPAnth),N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine(abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine(abbreviation: DPhPA), YGAPA, PCAPA,N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine(abbreviation: PCAPBA), 2PCAPA, 6,12-dimethoxy-5,11-diphenylchrysene,DBC1,9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation:CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole(abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)anthracene(abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA),2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA),9,9′-bianthryl (abbreviation: BANT),9,9′-(stilbene-3,3′-diyl)diphenanthrene (abbreviation: DPNS),9,9′-(stilbene-4,4′-diyl)diphenanthrene (abbreviation: DPNS2), and1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3).

In the case where a plurality of organic compounds are used for thelight-emitting layers (113, 113 a, 113 b, and 113 c), it is possible touse two compounds that form an exciplex (a first compound and a secondcompound) combined with an organometallic complex. In that case,although any of various organic compounds can be used in an appropriatecombination, in order to form an exciplex efficiently, it isparticularly preferable to combine a compound that easily accepts holes(a hole-transport material) and a compound that easily accepts electrons(an electron-transport material). As the hole-transport material and theelectron-transport material, specifically, any of the materialsdescribed in this embodiment can be used. With the above structure, highefficiency, low voltage, and a long lifetime can be achieved at the sametime.

The TADF material is a material that can up-convert a triplet excitedstate into a singlet excited state (i.e., reverse intersystem crossingis possible) using a little thermal energy and efficiently exhibitslight emission (fluorescence) from the singlet excited state. The TADFis efficiently obtained under the condition where the difference inenergy between the triplet excited level and the singlet excited levelis greater than or equal to 0 eV and less than or equal to 0.2 eV,preferably greater than or equal to 0 eV and less than or equal to 0.1eV. Note that “delayed fluorescence” exhibited by the TADF materialrefers to light emission having the same spectrum as normal fluorescenceand an extremely long lifetime. The lifetime is 10-seconds or longer,preferably 10⁻³ seconds or longer.

Examples of the TADF material include fullerene, a derivative thereof,an acridine derivative such as proflavine, and eosin. Other examplesinclude a metal-containing porphyrin, such as a porphyrin containingmagnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium(In), or palladium (Pd). Examples of the metal-containing porphyrininclude a protoporphyrin-tin fluoride complex (abbreviation: SnF₂(ProtoIX)), a mesoporphyrin-tin fluoride complex (abbreviation: SnF₂(MesoIX)), a hematoporphyrin-tin fluoride complex (abbreviation: SnF₂(HematoIX)), a coproporphyrin tetramethyl ester-tin fluoride complex(abbreviation: SnF₂(Copro III-4Me)), an octaethylporphyrin-tin fluoridecomplex (abbreviation: SnF₂(OEP)), an etioporphyrin-tin fluoride complex(abbreviation: SnF₂(Etio I)), and an octaethylporphyrin-platinumchloride complex (abbreviation: PtCl₂OEP).

Alternatively, a heterocyclic compound having a π-electron richheteroaromatic ring and a π-electron deficient heteroaromatic ring, suchas2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine(abbreviation: PIC-TRZ),2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine(abbreviation: PCCzPTzn), 2-[4-(10OH-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation:PXZ-TRZ),3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole(abbreviation: PPZ-3TPT),3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation:ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone(abbreviation: DMAC-DPS), or10-phenyl-10H,10′H-spiro[acridin-9,9′-anthracen]-10′-one (abbreviation:ACRSA) can be used. Note that a substance in which the π-electron richheteroaromatic ring is directly bonded to the π-electron deficientheteroaromatic ring is particularly preferable because both the donorproperty of the π-electron rich heteroaromatic ring and the acceptorproperty of the π-electron deficient heteroaromatic ring are increasedand the energy difference between the singlet excited state and thetriplet excited state becomes small.

Note that when a TADF material is used, the TADF material can becombined with another organic compound. In particular, the TADF materialcan be combined with the host materials, the hole-transport materials,and the electron-transport materials described above. The organiccompound of one embodiment of the present invention described inEmbodiment 1 is preferably used as a host material combined with theTADF material.

In the light-emitting element in FIG. 1D, an electron-transport layer114 a is formed over the light-emitting layer 113 a of the EL layer 103a by a vacuum evaporation method. After the EL layer 103 a and thecharge-generation layer 104 are formed, an electron-transport layer 114b is formed over the light-emitting layer 113 b of the EL layer 103 b bya vacuum evaporation method.

<Electron-Transport Layer>

The electron-transport layers (114, 114 a, and 114 b) transport theelectrons, which are injected from the second electrode 102 and thecharge-generation layer (104) by the electron-injection layers (115, 115a, and 115 b), to the light-emitting layers (113, 113 a, and 113 b).Note that the electron-transport layers (114, 114 a, and 114 b) eachcontain an electron-transport material. It is preferable that theelectron-transport materials included in the electron-transport layers(114, 114 a, and 114 b) be substances with an electron mobility ofhigher than or equal to 1×10⁻⁶ cm²NVs. Note that other substances mayalso be used as long as the substances have an electron-transportproperty higher than a hole-transport property. The organic compound ofone embodiment of the present invention described in Embodiment 1 has anexcellent electron-transport property and thus can also be used for anelectron-transport layer.

Examples of the electron-transport material include metal complexeshaving a quinoline ligand, a benzoquinoline ligand, an oxazole ligand,and a thiazole ligand; an oxadiazole derivative; a triazole derivative;a phenanthroline derivative; a pyridine derivative; and a bipyridinederivative. In addition, a π-electron deficient heteroaromatic compoundsuch as a nitrogen-containing heteroaromatic compound can also be used.

Specifically, it is possible to use metal complexes such as Alq₃,tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq₃),bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq₂),BAlq, bis[2-(2-hydroxyphenyl)benzoxazolato]zinc(II) (abbreviation:Zn(BOX)₂), and bis[2-(2-hydroxyphenyl)benzothiazolato]zinc(II)(abbreviation: Zn(BTZ)₂), heteroaromatic compounds such as2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation:PBD),OXD-7,3-(4′-tert-butylphenyl)-4-phenyl-5-(4″-biphenyl)-1,2,4-triazole(abbreviation: TAZ),3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole(abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: Bphen),bathocuproine (abbreviation: BCP), and4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), andquinoxaline derivatives and dibenzoquinoxaline derivatives such as2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:2mDBTPDBq-II),2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II),2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline(abbreviation: 2CzPDBq-III),7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:7mDBTPDBq-II), and6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation:6mDBTPDBq-II).

Alternatively, a high molecular compound such as poly(2,5-pyridinediyl)(abbreviation: PPy),poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)](abbreviation:PF-Py), orpoly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2′-bipyridine-6,6′-diyl)](abbreviation: PF-BPy) can be used.

Each of the electron-transport layers (114, 114 a, and 114 b) is notlimited to a single layer, and may be a stack of two or more layers eachcontaining any of the above substances.

In the light-emitting element in FIG. 1D, the electron-injection layer115 a is formed over the electron-transport layer 114 a of the EL layer103 a by a vacuum evaporation method. Subsequently, the EL layer 103 aand the charge-generation layer 104 are formed, the components up to theelectron-transport layer 114 b of the EL layer 103 b are formed, andthen the electron-injection layer 115 b is formed thereover by a vacuumevaporation method.

<Electron-Injection Layer>

The electron-injection layers (115, 115 a, and 115 b) each contain asubstance having a high electron-injection property. Theelectron-injection layers (115, 115 a, and 115 b) can each be formedusing an alkali metal, an alkaline earth metal, or a compound thereof,such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride(CaF₂), or lithium oxide (LiO_(x)). A rare earth metal compound likeerbium fluoride (ErF₃) can also be used. Electride may also be used forthe electron-injection layers (115, 115 a, and 115 b). Examples of theelectride include a substance in which electrons are added at highconcentration to calcium oxide-aluminum oxide. Any of the substances forforming the electron-transport layers (114, 114 a, and 114 b), which aregiven above, can also be used.

A composite material in which an organic compound and an electron donor(donor) are mixed may also be used for the electron-injection layers(115, 115 a, and 115 b). Such a composite material is excellent in anelectron-injection property and an electron-transport property becauseelectrons are generated in the organic compound by the electron donor.The organic compound here is preferably a material excellent intransporting the generated electrons; specifically, for example, theelectron-transport materials for forming the electron-transport layers(114, 114 a, and 114 b) (e.g., a metal complex or a heteroaromaticcompound) can be used. As the electron donor, a substance showing anelectron-donating property with respect to the organic compound may beused. Preferable examples are an alkali metal, an alkaline earth metal,and a rare earth metal. Specifically, lithium, cesium, magnesium,calcium, erbium, ytterbium, and the like can be given. Furthermore, analkali metal oxide and an alkaline earth metal oxide are preferable, anda lithium oxide, a calcium oxide, a barium oxide, and the like can begiven. Alternatively, a Lewis base such as magnesium oxide can be used.Further alternatively, an organic compound such as tetrathiafulvalene(abbreviation: TTF) can be used.

In the case where light obtained from the light-emitting layer 113 b isamplified, for example, the optical path length between the secondelectrode 102 and the light-emitting layer 113 b is preferably less thanone fourth of the wavelength λ of light emitted from the light-emittinglayer 113 b. In that case, the optical path length can be adjusted bychanging the thickness of the electron-transport layer 114 b or theelectron-injection layer 115 b.

<Charge-Generation Layer>

The charge-generation layer 104 has a function of injecting electronsinto the EL layer 103 a and injecting holes into the EL layer 103 b whenvoltage is applied between the first electrode (anode) 101 and thesecond electrode (cathode) 102. The charge-generation layer 104 may haveeither a structure in which an electron acceptor (acceptor) is added toa hole-transport material or a structure in which an electron donor(donor) is added to an electron-transport material. Alternatively, bothof these structures may be stacked. Note that forming thecharge-generation layer 104 by using any of the above materials cansuppress an increase in drive voltage caused by the stack of the ELlayers.

In the case where the charge-generation layer 104 has a structure inwhich an electron acceptor is added to a hole-transport material, any ofthe materials described in this embodiment can be used as thehole-transport material. As the electron acceptor, it is possible to use7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation:F₄-TCNQ), chloranil, and the like. In addition, oxides of metals thatbelong to Group 4 to Group 8 of the periodic table can be given.Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromiumoxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide,or the like is used.

In the case where the charge-generation layer 104 has a structure inwhich an electron donor is added to an electron-transport material, anyof the materials described in this embodiment can be used as theelectron-transport material. As the electron donor, it is possible touse an alkali metal, an alkaline earth metal, a rare earth metal, metalsthat belong to Groups 2 and 13 of the periodic table, or an oxide orcarbonate thereof. Specifically, lithium (Li), cesium (Cs), magnesium(Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesiumcarbonate, or the like is preferably used. Alternatively, an organiccompound such as tetrathianaphthacene may be used as the electron donor.

Note that the EL layer 103 c in FIG. 1E has a structure similar to thoseof the above-described EL layers (103, 103 a, and 103 b). In addition,the charge-generation layers 104 a and 104 b each have a structuresimilar to that of the above-described charge-generation layer 104.

<Substrate>

The light-emitting element described in this embodiment can be formedover any of a variety of substrates. Note that the type of the substrateis not limited to a certain type. Examples of the substrate include asemiconductor substrate (e.g., a single crystal substrate or a siliconsubstrate), an SOI substrate, a glass substrate, a quartz substrate, aplastic substrate, a metal substrate, a stainless steel substrate, asubstrate including stainless steel foil, a tungsten substrate, asubstrate including tungsten foil, a flexible substrate, an attachmentfilm, paper including a fibrous material, and a base material film.

Examples of the glass substrate include a barium borosilicate glasssubstrate, an aluminoborosilicate glass substrate, and a soda lime glasssubstrate. Examples of the flexible substrate, the attachment film, andthe base material film include plastics typified by polyethyleneterephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES); a synthetic resin such as acrylic; polypropylene;polyester, polyvinyl fluoride; polyvinyl chloride; polyamide; polyimide;aramid; epoxy; an inorganic vapor deposition film; and paper.

For fabrication of the light-emitting element in this embodiment, avacuum process such as an evaporation method or a solution process suchas a spin coating method or an ink-jet method can be used. When anevaporation method is used, a physical vapor deposition method (PVDmethod) such as a sputtering method, an ion plating method, an ion beamevaporation method, a molecular beam evaporation method, or a vacuumevaporation method, a chemical vapor deposition method (CVD method), orthe like can be used. Specifically, the functional layers (thehole-injection layers (111, 111 a, and 111 b), the hole-transport layers(112, 112 a, and 112 b), the light-emitting layers (113, 113 a, 113 b,and 113 c), the electron-transport layers (114, 114 a, and 114 b), theelectron-injection layers (115, 115 a, and 115 b)) included in the ELlayers and the charge-generation layers (104, 104 a, and 104 b) of thelight-emitting element can be formed by an evaporation method (e.g., avacuum evaporation method), a coating method (e.g., a dip coatingmethod, a die coating method, a bar coating method, a spin coatingmethod, or a spray coating method), a printing method (e.g., an ink-jetmethod, screen printing (stencil), offset printing (planography),flexography (relief printing), gravure printing, or micro-contactprinting), or the like.

Note that materials that can be used for the functional layers (thehole-injection layers (111, 111 a, and 111 b), the hole-transport layers(112, 112 a, and 112 b), the light-emitting layers (113, 113 a, 113 b,and 113 c), the electron-transport layers (114, 114 a, and 114 b), andthe electron-injection layers (115, 115 a, and 115 b)) that are includedin the EL layers (103, 103 a, and 103 b) and the charge-generationlayers (104, 104 a, and 104 b) in the light-emitting element describedin this embodiment are not limited to the above materials, and othermaterials can be used in combination as long as the functions of thelayers are fulfilled. For example, a high molecular compound (e.g., anoligomer, a dendrimer, or a polymer), a middle molecular compound (acompound between a low molecular compound and a high molecular compoundwith a molecular weight of 400 to 4000), an inorganic compound (e.g., aquantum dot material), or the like can be used. The quantum dot may be acolloidal quantum dot, an alloyed quantum dot, a core-shell quantum dot,a core quantum dot, or the like.

The structures described in this embodiment can be combined with any ofthe structures described in the other embodiments as appropriate.

Embodiment 3

In this embodiment, a light-emitting device of one embodiment of thepresent invention is described. Note that a light-emitting deviceillustrated in FIG. 2A is an active-matrix light-emitting device inwhich transistors (FETs) 202 are electrically connected tolight-emitting elements (203R, 203G, 203B, and 203W) over a firstsubstrate 201. The light-emitting elements (203R, 203G, 203B, and 203W)include a common EL layer 204 and each have a microcavity structure inwhich the optical path length between electrodes is adjusted dependingon the emission color of the light-emitting element. The light-emittingdevice is a top-emission light-emitting device in which light is emittedfrom the EL layer 204 through color filters (206R, 206G, and 206B)formed on a second substrate 205.

The light-emitting device illustrated in FIG. 2A is fabricated such thata first electrode 207 functions as a reflective electrode and a secondelectrode 208 functions as a transflective electrode. Note thatdescription in any of the other embodiments can be referred to asappropriate for electrode materials for the first electrode 207 and thesecond electrode 208.

In the case where the light-emitting element 203R functions as a redlight-emitting element, the light-emitting element 203G functions as agreen light-emitting element, the light-emitting element 203B functionsas a blue light-emitting element, and the light-emitting element 203Wfunctions as a white light-emitting element in FIG. 2A, for example, agap between the first electrode 207 and the second electrode 208 in thelight-emitting element 203R is adjusted to have an optical path length200R, a gap between the first electrode 207 and the second electrode 208in the light-emitting element 203G is adjusted to have an optical pathlength 200G, and a gap between the first electrode 207 and the secondelectrode 208 in the light-emitting element 203B is adjusted to have anoptical path length 200B as illustrated in FIG. 2B. Note that opticaladjustment can be performed in such a manner that a conductive layer210R is stacked over the first electrode 207 in the light-emittingelement 203R and a conductive layer 210G is stacked over the firstelectrode 207 in the light-emitting element 203G as illustrated in FIG.2B.

The second substrate 205 is provided with the color filters (206R, 206G,and 206B). Note that the color filters each transmit visible light in aspecific wavelength range and blocks visible light in a specificwavelength range. Thus, as illustrated in FIG. 2A, the color filter 206Rthat transmits only light in the red wavelength range is provided in aposition overlapping with the light-emitting element 203R, whereby redlight emission can be obtained from the light-emitting element 203R.Furthermore, the color filter 206G that transmits only light in thegreen wavelength range is provided in a position overlapping with thelight-emitting element 203G, whereby green light emission can beobtained from the light-emitting element 203G. Moreover, the colorfilter 206B that transmits only light in the blue wavelength range isprovided in a position overlapping with the light-emitting element 203B,whereby blue light emission can be obtained from the light-emittingelement 203B. Note that the light-emitting element 203W can emit whitelight without a color filter. Note that a black layer (black matrix) 209may be provided at an end portion of each color filter. The colorfilters (206R, 206G, and 206B) and the black layer 209 may be coveredwith an overcoat layer formed using a transparent material.

Although the light-emitting device in FIG. 2A has a structure in whichlight is extracted from the second substrate 205 side (top emissionstructure), a structure in which light is extracted from the firstsubstrate 201 side where the FETs 202 are formed (bottom emissionstructure) may be employed as illustrated in FIG. 2C. In the case of abottom-emission light-emitting device, the first electrode 207 is formedas a transflective electrode and the second electrode 208 is formed as areflective electrode. As the first substrate 201, a substrate having atleast a light-transmitting property is used. As illustrated in FIG. 2C,color filters (206R′, 206G′, and 206B′) are provided so as to be closerto the first substrate 201 than the light-emitting elements (203R, 203G,and 203B) are.

In FIG. 2A, the light-emitting elements are the red light-emittingelement, the green light-emitting element, the blue light-emittingelement, and the white light-emitting element; however, thelight-emitting elements of one embodiment of the present invention arenot limited to the above, and a yellow light-emitting element or anorange light-emitting element may be used. Note that description in anyof the other embodiments can be referred to as appropriate for materialsthat are used for the EL layers (a light-emitting layer, ahole-injection layer, a hole-transport layer, an electron-transportlayer, an electron-injection layer, a charge-generation layer, and thelike) to fabricate each of the light-emitting elements. In that case, acolor filter needs to be appropriately selected depending on theemission color of the light-emitting element.

With the above structure, a light-emitting device includinglight-emitting elements that exhibit a plurality of emission colors canbe fabricated.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 4

In this embodiment, a light-emitting device of one embodiment of thepresent invention is described.

The use of the element structure of the light-emitting element of oneembodiment of the present invention allows fabrication of anactive-matrix light-emitting device or a passive-matrix light-emittingdevice. Note that an active-matrix light-emitting device has a structureincluding a combination of a light-emitting element and a transistor(FET). Thus, each of a passive-matrix light-emitting device and anactive-matrix light-emitting device is one embodiment of the presentinvention. Note that any of the light-emitting elements described inother embodiments can be used in the light-emitting device described inthis embodiment.

In this embodiment, an active-matrix light-emitting device will bedescribed with reference to FIGS. 3A and 3B.

FIG. 3A is a top view illustrating the light-emitting device, and FIG.3B is a cross-sectional view taken along chain line A-A′ in FIG. 3A. Theactive-matrix light-emitting device includes a pixel portion 302, adriver circuit portion (source line driver circuit) 303, and drivercircuit portions (gate line driver circuits) (304 a and 304 b) that areprovided over a first substrate 301. The pixel portion 302 and thedriver circuit portions (303, 304 a, and 304 b) are sealed between thefirst substrate 301 and a second substrate 306 with a sealant 305.

A lead wiring 307 is provided over the first substrate 301. The leadwiring 307 is connected to an FPC 308 that is an external inputterminal. Note that the FPC 308 transmits a signal (e.g., a videosignal, a clock signal, a start signal, or a reset signal) or apotential from the outside to the driver circuit portions (303, 304 a,and 304 b). The FPC 308 may be provided with a printed wiring board(PWB). Note that the light-emitting device provided with an FPC or a PWBis included in the category of a light-emitting device.

FIG. 3B illustrates a cross-sectional structure of the light-emittingdevice.

The pixel portion 302 includes a plurality of pixels each of whichincludes an FET (switching FET) 311, an FET (current control FET) 312,and a first electrode 313 electrically connected to the FET 312. Notethat the number of FETs included in each pixel is not particularlylimited and can be set appropriately.

As FETs 309, 310, 311, and 312, for example, a staggered transistor oran inverted staggered transistor can be used without particularlimitation. A top-gate transistor, a bottom-gate transistor, or the likemay be used.

Note that there is no particular limitation on the crystallinity of asemiconductor that can be used for the FETs 309, 310, 311, and 312, andan amorphous semiconductor or a semiconductor having crystallinity (amicrocrystalline semiconductor, a polycrystalline semiconductor, asingle crystal semiconductor, or a semiconductor partly includingcrystal regions) may be used. A semiconductor having crystallinity ispreferably used, in which case deterioration of the transistorcharacteristics can be suppressed.

For the semiconductor, a Group 14 element, a compound semiconductor, anoxide semiconductor, an organic semiconductor, or the like can be used,for example. As a typical example, a semiconductor containing silicon, asemiconductor containing gallium arsenide, or an oxide semiconductorcontaining indium can be used.

The driver circuit portion 303 includes the FET 309 and the FET 310. TheFET 309 and the FET 310 may be formed with a circuit includingtransistors having the same conductivity type (either n-channeltransistors or p-channel transistors) or a CMOS circuit including ann-channel transistor and a p-channel transistor. Furthermore, a drivercircuit may be provided outside.

An end portion of the first electrode 313 is covered with an insulator314. The insulator 314 can be formed using an organic compound such as anegative photosensitive resin or a positive photosensitive resin(acrylic resin), or an inorganic compound such as silicon oxide, siliconoxynitride, or silicon nitride. The insulator 314 preferably has acurved surface with curvature at an upper end portion or a lower endportion thereof. In that case, favorable coverage with a film formedover the insulator 314 can be obtained.

An EL layer 315 and a second electrode 316 are stacked over the firstelectrode 313. The EL layer 315 includes a light-emitting layer, ahole-injection layer, a hole-transport layer, an electron-transportlayer, an electron-injection layer, a charge-generation layer, and thelike.

The structure and materials described in any of the other embodimentscan be used for the components of a light-emitting element 317 describedin this embodiment. Although not illustrated, the second electrode 316is electrically connected to the FPC 308 that is an external inputterminal.

Although the cross-sectional view in FIG. 3B illustrates only onelight-emitting element 317, a plurality of light-emitting elements arearranged in a matrix in the pixel portion 302. Light-emitting elementsthat emit light of three kinds of colors (R, G, and B) are selectivelyformed in the pixel portion 302, whereby a light-emitting device capableof displaying a full-color image can be obtained. In addition to thelight-emitting elements that emit light of three kinds of colors (R, G,and B), for example, light-emitting elements that emit light of white(W), yellow (Y), magenta (M), cyan (C), and the like may be formed. Forexample, the light-emitting elements that emit light of some of theabove colors are used in combination with the light-emitting elementsthat emit light of three kinds of colors (R, G, and B), whereby effectssuch as an improvement in color purity and a reduction in powerconsumption can be achieved. Alternatively, a light-emitting devicewhich is capable of displaying a full-color image may be fabricated by acombination with color filters. As color filters, red (R), green (G),blue (B), cyan (C), magenta (M), and yellow (Y) color filters and thelike can be used.

When the second substrate 306 and the first substrate 301 are bonded toeach other with the sealant 305, the FETs (309, 310, 311, and 312) andthe light-emitting element 317 over the first substrate 301 are providedin a space 318 surrounded by the first substrate 301, the secondsubstrate 306, and the sealant 305. Note that the space 318 may befilled with an inert gas (e.g., nitrogen or argon) or an organicsubstance (including the sealant 305).

An epoxy-based resin, glass frit, or the like can be used for thesealant 305. It is preferable to use a material that is permeable to aslittle moisture and oxygen as possible for the sealant 305. As thesecond substrate 306, a substrate that can be used as the firstsubstrate 301 can be similarly used. Thus, any of the various substratesdescribed in the other embodiments can be appropriately used. As thesubstrate, a glass substrate, a quartz substrate, or a plastic substratemade of fiber-reinforced plastic (FRP), polyvinyl fluoride (PVF),polyester, acrylic, or the like can be used. In the case where glassfrit is used for the sealant, the first substrate 301 and the secondsubstrate 306 are preferably glass substrates in terms of adhesion.

Accordingly, the active-matrix light-emitting device can be obtained.

In the case where the active-matrix light-emitting device is providedover a flexible substrate, the FETs and the light-emitting element maybe directly formed over the flexible substrate; alternatively, the FETsand the light-emitting element may be formed over a substrate providedwith a separation layer and then separated at the separation layer byapplication of heat, force, laser, or the like to be transferred to aflexible substrate. For the separation layer, a stack includinginorganic films such as a tungsten film and a silicon oxide film, or anorganic resin film of polyimide or the like can be used, for example.Examples of the flexible substrate include, in addition to a substrateover which a transistor can be formed, a paper substrate, a cellophanesubstrate, an aramid film substrate, a polyimide film substrate, a clothsubstrate (including a natural fiber (e.g., silk, cotton, or hemp), asynthetic fiber (e.g., nylon, polyurethane, or polyester), a regeneratedfiber (e.g., acetate, cupra, rayon, or regenerated polyester), or thelike), a leather substrate, and a rubber substrate. With the use of anyof these substrates, an increase in durability, an increase in heatresistance, a reduction in weight, and a reduction in thickness can beachieved.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 5

In this embodiment, examples of a variety of electronic devices and anautomobile manufactured using the light-emitting device of oneembodiment of the present invention or a display device including thelight-emitting element of one embodiment of the present invention aredescribed.

Electronic devices illustrated in FIGS. 4A to 4E can include a housing7000, a display portion 7001, a speaker 7003, an LED lamp 7004,operation keys 7005 (including a power switch or an operation switch), aconnection terminal 7006, a sensor 7007 (a sensor having a function ofmeasuring or sensing force, displacement, position, speed, acceleration,angular velocity, rotational frequency, distance, light, liquid,magnetism, temperature, chemical substance, sound, time, hardness,electric field, current, voltage, electric power, radiation, flow rate,humidity, gradient, oscillation, odor, or infrared ray), a microphone7008, and the like.

FIG. 4A illustrates a mobile computer that can include a switch 7009, aninfrared port 7010, and the like in addition to the above components.

FIG. 4B illustrates a portable image reproducing device (e.g., a DVDplayer) that is provided with a recording medium and can include asecond display portion 7002, a recording medium reading portion 7011,and the like in addition to the above components.

FIG. 4C illustrates a goggle-type display that can include the seconddisplay portion 7002, a support 7012, an earphone 7013, and the like inaddition to the above components.

FIG. 4D illustrates a digital camera that has a television receptionfunction and can include an antenna 7014, a shutter button 7015, animage receiving portion 7016, and the like in addition to the abovecomponents.

FIG. 4E illustrates a cellular phone (including a smartphone) that caninclude the display portion 7001, a microphone 7019, the speaker 7003, acamera 7020, an external connection portion 7021, an operation button7022, and the like in the housing 7000.

FIG. 4F illustrates a large-size television set (also referred to as TVor a television receiver) that can include the housing 7000, the displayportion 7001, and the like. In addition, here, the housing 7000 issupported by a stand 7018. The television set can be operated with aseparate remote controller 7111 or the like. The display portion 7001may include a touch sensor. The television set can be operated bytouching the display portion 7001 with a finger or the like. The remotecontroller 7111 may be provided with a display portion for displayinginformation output from the remote controller 7111. With operation keysor a touch panel of the remote controller 7111, channels and volume canbe controlled and images displayed on the display portion 7001 can becontrolled.

The electronic devices illustrated in FIGS. 4A to 4F can have a varietyof functions, such as a function of displaying a variety of information(a still image, a moving image, a text image, and the like) on thedisplay portion, a touch panel function, a function of displaying acalendar, date, time, and the like, a function of controlling processingwith a variety of types of software (programs), a wireless communicationfunction, a function of connecting to a variety of computer networkswith a wireless communication function, a function of transmitting andreceiving a variety of data with a wireless communication function, afunction of reading a program or data stored in a recording medium anddisplaying the program or data on the display portion, and the like.Furthermore, the electronic device including a plurality of displayportions can have a function of displaying image data mainly on onedisplay portion while displaying text data mainly on another displayportion, a function of displaying a three-dimensional image bydisplaying images on a plurality of display portions with a parallaxtaken into account, or the like. Furthermore, the electronic deviceincluding an image receiving portion can have a function of taking astill image, a function of taking a moving image, a function ofautomatically or manually correcting a taken image, a function ofstoring a taken image in a recording medium (an external recordingmedium or a recording medium incorporated in the camera), a function ofdisplaying a taken image on the display portion, or the like. Note thatfunctions that can be provided for the electronic devices illustrated inFIGS. 4A to 4F are not limited to those described above, and theelectronic devices can have a variety of functions.

FIG. 4G illustrates a smart watch, which includes the housing 7000, thedisplay portion 7001, operation buttons 7022 and 7023, a connectionterminal 7024, a band 7025, a clasp 7026, and the like.

The display portion 7001 mounted in the housing 7000 serving as a bezelincludes a non-rectangular display region. The display portion 7001 candisplay an icon 7027 indicating time, another icon 7028, and the like.The display portion 7001 may be a touch panel (an input/output device)including a touch sensor (an input device).

The smart watch illustrated in FIG. 4G can have a variety of functions,such as a function of displaying a variety of information (e.g., a stillimage, a moving image, and a text image) on the display portion, a touchpanel function, a function of displaying a calendar, date, time, and thelike, a function of controlling processing with a variety of types ofsoftware (programs), a wireless communication function, a function ofconnecting to a variety of computer networks with a wirelesscommunication function, a function of transmitting and receiving avariety of data with a wireless communication function, a function ofreading a program or data stored in a recording medium and displayingthe program or data on the display portion, and the like.

The housing 7000 can include a speaker, a sensor (a sensor having afunction of measuring or sensing force, displacement, position, speed,acceleration, angular velocity, rotational frequency, distance, light,liquid, magnetism, temperature, chemical substance, sound, time,hardness, electric field, current, voltage, electric power, radiation,flow rate, humidity, gradient, oscillation, odor, or infrared rays), amicrophone, and the like.

Note that the light-emitting device of one embodiment of the presentinvention or the display device including the light-emitting element ofone embodiment of the present invention can be used in the displayportion of each electronic device described in this embodiment, so thata long lifetime electronic device can be obtained.

Another electronic device including the light-emitting device is afoldable portable information terminal illustrated in FIGS. 5A to 5C.FIG. 5A illustrates a portable information terminal 9310 which isopened. FIG. 5B illustrates the portable information terminal 9310 whichis being opened or being folded. FIG. 5C illustrates the portableinformation terminal 9310 which is folded. The portable informationterminal 9310 is highly portable when folded. The portable informationterminal 9310 is highly browsable when opened because of a seamlesslarge display region.

A display portion 9311 is supported by three housings 9315 joinedtogether by hinges 9313. Note that the display portion 9311 may be atouch panel (an input/output device) including a touch sensor (an inputdevice). By bending the display portion 9311 at a connection portionbetween two housings 9315 with the use of the hinges 9313, the portableinformation terminal 9310 can be reversibly changed in shape from anopened state to a folded state. The light-emitting device of oneembodiment of the present invention can be used for the display portion9311. In addition, a long lifetime electronic device can be obtained. Adisplay region 9312 in the display portion 9311 is a display region thatis positioned at a side surface of the portable information terminal9310 which is folded. On the display region 9312, information icons,file shortcuts of frequently used applications or programs, and the likecan be displayed, and confirmation of information and start ofapplication and the like can be smoothly performed.

FIGS. 6A and 6B illustrate an automobile including the light-emittingdevice. The light-emitting device can be incorporated in the automobile,and specifically, can be included in lights 5101 (including lights ofthe rear part of the car), a wheel cover 5102, a part or whole of a door5103, or the like on the outer side of the automobile which isillustrated in FIG. 6A. The light-emitting device can also be includedin a display portion 5104, a steering wheel 5105, a gear lever 5106, aseat 5107, an inner rearview mirror 5108, or the like on the inner sideof the automobile which is illustrated in FIG. 6B, or in a part of aglass window.

In the above manner, the electronic devices and automobiles can beobtained using the light-emitting device or the display device of oneembodiment of the present invention. In that case, a long lifetimeelectronic device can be obtained. Note that the light-emitting deviceor the display device can be used for electronic devices and automobilesin a variety of fields without being limited to those described in thisembodiment.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 6

In this embodiment, a structure of a lighting device fabricated usingthe light-emitting device of one embodiment of the present invention orthe light-emitting element which is a part of the light-emitting deviceis described with reference to FIGS. 7A to 7D.

FIGS. 7A to 7D are examples of cross-sectional views of lightingdevices. FIGS. 7A and 7B illustrate bottom-emission lighting devices inwhich light is extracted from the substrate side, and FIGS. 7C and 7Dillustrate top-emission lighting devices in which light is extractedfrom the sealing substrate side.

A lighting device 4000 illustrated in FIG. 7A includes a light-emittingelement 4002 over a substrate 4001. In addition, the lighting device4000 includes a substrate 4003 with unevenness on the outside of thesubstrate 4001. The light-emitting element 4002 includes a firstelectrode 4004, an EL layer 4005, and a second electrode 4006.

The first electrode 4004 is electrically connected to an electrode 4007,and the second electrode 4006 is electrically connected to an electrode4008. In addition, an auxiliary wiring 4009 electrically connected tothe first electrode 4004 may be provided. Note that an insulating layer4010 is formed over the auxiliary wiring 4009.

The substrate 4001 and a sealing substrate 4011 are bonded to each otherwith a sealant 4012. A desiccant 4013 is preferably provided between thesealing substrate 4011 and the light-emitting element 4002. Thesubstrate 4003 has the unevenness illustrated in FIG. 7A, whereby theextraction efficiency of light emitted from the light-emitting element4002 can be increased.

Instead of the substrate 4003, a diffusion plate 4015 may be provided onthe outside of the substrate 4001 as in a lighting device 4100illustrated in FIG. 7B.

A lighting device 4200 illustrated in FIG. 7C includes a light-emittingelement 4202 over a substrate 4201. The light-emitting element 4202includes a first electrode 4204, an EL layer 4205, and a secondelectrode 4206.

The first electrode 4204 is electrically connected to an electrode 4207,and the second electrode 4206 is electrically connected to an electrode4208. An auxiliary wiring 4209 electrically connected to the secondelectrode 4206 may be provided. An insulating layer 4210 may be providedunder the auxiliary wiring 4209.

The substrate 4201 and a sealing substrate 4211 with unevenness arebonded to each other with a sealant 4212. A barrier film 4213 and aplanarization film 4214 may be provided between the sealing substrate4211 and the light-emitting element 4202. The sealing substrate 4211 hasthe unevenness illustrated in FIG. 7C, whereby the extraction efficiencyof light emitted from the light-emitting element 4202 can be increased.

Instead of the sealing substrate 4211, a diffusion plate 4215 may beprovided over the light-emitting element 4202 as in a lighting device4300 illustrated in FIG. 7D.

Note that with the use of the light-emitting device of one embodiment ofthe present invention or the light-emitting element which is a part ofthe light-emitting device as described in this embodiment, a lightingdevice having desired chromaticity can be provided.

Note that the structures described in this embodiment can be combinedwith any of the structures described in the other embodiments asappropriate.

Embodiment 7

In this embodiment, application examples of lighting devices fabricatedusing the light-emitting device of one embodiment of the presentinvention or the light-emitting element which is a part of thelight-emitting device will be described with reference to FIG. 8.

A ceiling light 8001 can be used as an indoor lighting device. Examplesof the ceiling light 8001 include a direct-mount light and an embeddedlight. Such a lighting device is fabricated using the light-emittingdevice and a housing or a cover in combination. Besides, application toa cord pendant light (light that is suspended from a ceiling by a cord)is also possible.

A foot light 8002 lights a floor so that safety on the floor can beimproved. For example, it can be effectively used in a bedroom, on astaircase, or on a passage. In that case, the size or shape of the footlight can be changed depending on the area or structure of a room. Thefoot light 8002 can be a stationary lighting device fabricated using thelight-emitting device and a support in combination.

A sheet-like lighting 8003 is a thin sheet-like lighting device. Thesheet-like lighting, which is attached to a wall when used, isspace-saving and thus can be used for a wide variety of uses.Furthermore, the area of the sheet-like lighting can be easilyincreased. The sheet-like lighting can also be used on a wall or housinghaving a curved surface.

In addition, a lighting device 8004 in which the direction of light froma light source is controlled to be only a desired direction can be used.

Besides the above examples, when the light-emitting device of oneembodiment of the present invention or the light-emitting element whichis a part of the light-emitting device is used as part of furniture in aroom, a lighting device that functions as the furniture can be obtained.

As described above, a variety of lighting devices that include thelight-emitting device can be obtained. Note that these lighting devicesare also embodiments of the present invention.

The structures described in this embodiment can be combined with any ofthe structures described in the other embodiments as appropriate.

Example 1 Synthesis Example 1

This example describes a method for synthesizing9-[(3′-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mDBtBPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(100) in Embodiment 1. The structure of 9mDBtBPNfpr is shown below.

Step 1: Synthesis of6-chloro-3-(2-methoxynaphthalen-1-yl)pyrazin-2-amine

First, into a three-neck flask equipped with a reflux pipe were put 4.37g of 3-bromo-6-chloropyrazin-2-amine, 4.23 g of2-methoxynaphthalene-1-boronic acid, 4.14 g of potassium fluoride, and75 mL of dehydrated tetrahydrofuran, and the air in the flask wasreplaced with nitrogen. The mixture in the flask was degassed by beingstirred under reduced pressure, and then 0.57 g oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃) and4.5 mL of tri-tert-butylphosphine (abbreviation: P(tBu)₃) were addedthereto. The mixture was stirred at 80° C. for 54 hours to be reacted.

After a predetermined time elapsed, the obtained mixture was subjectedto suction filtration and the filtrate was concentrated. Then,purification by silica gel column chromatography using a developingsolvent (toluene:ethyl acetate=9:1) was performed, so that 2.19 g of atarget pyrazine derivative (yellowish white powder) was obtained in ayield of 36%. A synthesis scheme of Step 1 is shown in (a-1) below.

Step 2: Synthesis of 9-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine

Next, into a three-neck flask were put 2.18 g of6-chloro-3-(2-methoxynaphthalen-1-yl)pyrazin-2-amine obtained in Step 1,63 mL of dehydrated tetrahydrofuran, and 84 mL of a glacial acetic acid,and the air in the flask was replaced with nitrogen. After the flask wascooled down to −10° C., 2.8 mL of tert-butyl nitrite was dripped, andthe mixture was stirred at −10° C. for 30 minutes and at 0° C. for 3hours. After a predetermined time elapsed, 250 mL of water was added tothe obtained suspension and suction filtration was performed, so that1.48 g of a target pyrazine derivative (yellowish white powder) wasobtained in a yield of 77%. A synthesis scheme of Step 2 is shown in(a-2) below.

Step 3: Synthesis of9-[(3′-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(Abbreviation: 9mDBtBPNfpr)

Into a three-neck flask were put 1.48 g of9-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine obtained in Step 2, 3.41 gof 3′-(4-dibenzothiophene)-1,1′-biphenyl-3-boronic acid, 8.8 mL of a 2Mpotassium carbonate aqueous solution, 100 mL of toluene, and 10 mL ofethanol, and the air in the flask was replaced with nitrogen. Themixture in the flask was degassed by being stirred under reducedpressure, and then 0.84 g of bis(triphenylphosphine)palladium(II)dichloride (abbreviation: Pd(PPh₃)₂Cl₂) was added thereto. The mixturewas stirred at 80° C. for 18 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was dissolved in toluene, and the mixture wasfiltered through a filter aid in which Celite, alumina, and Celite werestacked in this order and was recrystallized with a mixed solvent oftoluene and hexane, so that 2.66 g of a target pale yellow solid wasobtained in a yield of 82%.

By a train sublimation method, 2.64 g of the obtained pale yellow solidwas purified by sublimation. In the purification by sublimation, thesolid was heated at 315° C. under a pressure of 2.6 Pa with an argon gasflow rate of 15 m/min. After the purification by sublimation, 2.34 g ofa target pale yellow solid was obtained in a yield of 89%. A synthesisscheme of Step 3 is shown in (a-3) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe pale yellow solid obtained in Step 3 are shown below. FIG. 9 is the¹H-NMR chart. The results revealed that 9mDBtBPNfpr, the organiccompound represented by Structural Formula (100), was obtained in thisexample.

¹H-NMR. δ (CD₂Cl₂): 7.47-7.51 (m, 2H), 7.60-7.69 (m, 5H), 7.79-7.89 (m,6H), 8.05 (d, 1H), 8.10-8.11 (m, 2H), 8.18-8.23 (m, 3H), 8.53 (s, 1H),9.16 (d, 1H), 9.32 (s, 1H).

FIG. 10A shows an ultraviolet-visible absorption spectrum (hereinafter,simply referred to as “absorption spectrum”) and an emission spectrum of9mDBtBPNfpr in a toluene solution. The horizontal axis representswavelength and the vertical axes represent absorption intensity andemission intensity.

The absorption spectrum was measured with an ultraviolet-visiblespectrophotometer (V-550, produced by JASCO Corporation). To calculatethe absorption spectrum of 9mDBtBPNfpr in a toluene solution, theabsorption spectrum of toluene put in a quartz cell was measured andthen subtracted from the absorption spectrum of a toluene solution of9mDBtBPNfpr put in a quartz cell. The emission spectrum was measuredwith a fluorescence spectrophotometer (FS920 produced by HamamatsuPhotonics K.K.). The emission spectrum of 9mDBtBPNfpr in the toluenesolution was measured with the toluene solution of 9mDBtBPNfpr put in aquartz cell.

FIG. 10A shows that 9mDBtBPNfpr in the toluene solution has absorptionpeaks at around 370 nm and 380 nm and emission wavelength peaks ataround 400 nm and 421 nm (the excitation wavelength: 291 nm).

Next, the absorption spectrum and the emission spectrum of a solid thinfilm of 9mDBtBPNfpr were measured. The solid thin film was fabricatedover a quartz substrate by a vacuum evaporation method. The absorptionspectrum of the thin film was calculated using an absorbance (−log₁₀ [%T/(100−% R)]) obtained from the transmittance and reflectance of thethin film including the substrate. Note that % T representstransmittance and % R represents reflectance. The absorption spectrumwas measured with a UV-visible spectrophotometer (U-4100 produced byHitachi High-Technologies Corporation). The emission spectrum wasmeasured with a fluorescence spectrophotometer (FS920 produced byHamamatsu Photonics K.K.). The obtained absorption and emission spectraof the solid thin film are shown in FIG. 10B. The horizontal axisrepresents wavelength and the vertical axes represent absorptionintensity and emission intensity.

FIG. 10B shows that the solid thin film of 9mDBtBPNfpr has absorptionpeaks at around 377 nm and 395 nm and an emission wavelength peak ataround 489 nm (the excitation wavelength: 370 nm).

Accordingly, 9mDBtBPNfpr, the organic compound of one embodiment of thepresent invention, is a host material that is suitably used with aphosphorescent material that emits light with energy at a wavelengthlonger than or equal to that of red light. Note that 9mDBtBPNfpr, theorganic compound of one embodiment of the present invention, can also beused as a host material for a substance that emits phosphorescence inthe visible region or a light-emitting substance.

Next, the LUMO level of 9mDBtBPNfpr is described. The LUMO level wasestimated from the values of a reduction potential and potential energy(approximately −4.94 eV with respect to the vacuum level) of a referenceelectrode (Ag/Ag⁺), which were obtained by cyclic voltammetry (CV)measurement in a dimethylformamide solvent. Specifically, −4.94[eV]−(the value of the reduction potential)=the LUMO level. The measuredLUMO level calculated using the above formula was −3.05 eV. Thisindicates that 9mDBtBPNfpr accepts electrons easily and has highelectron stability.

Example 2

This example describes element structures, fabrication methods, andcharacteristics of a light-emitting element 1 (light-emitting element ofone embodiment of the present invention) in which9-[(3′-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mDBtBPNfpr) (Structural Formula (100)) described inExample 1 is used in a light-emitting layer and a comparativelight-emitting element 2 in which2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II) is used in a light-emitting layer. Notethat FIG. 11 illustrates an element structure of a light-emittingelement used in this example, and Table 1 shows specific structures.Chemical formulae of materials used in this example are shown below.

TABLE 1 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode 901 911 912 913 914 915 903 Light- ITSO DBT3P-II:MoOxBPAFLP * 9mDBtBPNfpr NBphen LiF Al emitting (70 nm) (2:1, 75 nm) (20 nm)(30 nm) (15 nm) (1 nm) (200 nm) element 1 Comparative ITSO DBT3P-II:MoOxBPAFLP ** 2mDBTBPDBq-II NBphen LiF Al light-emitting (70 nm) (2:1, 75nm) (20 nm) (30 nm) (15 nm) (1 nm) (200 nm) element 2 *9mDBtBPNfpr:PCBBiF:[Ir(dmdppr-P)₂(dibm)] (0.75:0.25:0.1, 40 nm) **2mDBTBPDBq-II:PCBBiF:[Ir(dmdppr-P)₂(dibm)] (0.75:0.25:0.1, 40 nm)

<<Fabrication of Light-Emitting Elements>>

In each of the light-emitting elements described in this example, asillustrated in FIG. 11, a hole-injection layer 911, a hole-transportlayer 912, a light-emitting layer 913, an electron-transport layer 914,and an electron-injection layer 915 are stacked in this order over afirst electrode 901 formed over a substrate 900, and a second electrode903 is stacked over the electron-injection layer 915.

First, the first electrode 901 was formed over the substrate 900. Theelectrode area was set to 4 mm² (2 mm×2 mm). A glass substrate was usedas the substrate 900. The first electrode 901 was formed to a thicknessof 70 nm using indium tin oxide containing silicon oxide (ITSO) by asputtering method.

As pretreatment, a surface of the substrate was washed with water,baking was performed at 200° C. for 1 hour, and then UV ozone treatmentwas performed for 370 seconds. After that, the substrate was transferredinto a vacuum evaporation apparatus where the pressure was reduced toapproximately 10⁻⁴ Pa, vacuum baking was performed at 170° C. for 30minutes in a heating chamber of the vacuum evaporation apparatus, andthen the substrate was cooled down for approximately 30 minutes.

Next, the hole-injection layer 911 was formed over the first electrode901. After the pressure in the vacuum evaporation apparatus was reducedto 10⁻⁴ Pa, the hole-injection layer 911 was formed by co-evaporation tohave a mass ratio of 1,3,5-tri(dibenzothiophen-4-yl)benzene(abbreviation: DBT3P-II) to molybdenum oxide of 2:1 and a thickness of75 nm.

Then, the hole-transport layer 912 was formed over the hole-injectionlayer 911. The hole-transport layer 912 was formed to a thickness of 20nm by evaporation of 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine(abbreviation: BPAFLP).

Next, the light-emitting layer 913 was formed over the hole-transportlayer 912.

The light-emitting layer 913 in the light-emitting element 1 was formedin the following manner: 9mDBtBPNfpr,N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), andbis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-N]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmdppr-P)₂(dibm)]), which was used as a guestmaterial (phosphorescent light-emitting material), were deposited byco-evaporation to have a weight ratio of 9mDBtBPNfpr to PCBBiF and[Ir(dmdppr-P)₂(dibm)] of 0.75:0.25:0.1. The thickness was set to 40 nm.The light-emitting layer 913 in the comparative light-emitting element 2was formed in the following manner: 2mDBTBPDBq-II, PCBBiF, and[Ir(dmdppr-P)₂(dibm)], which was used as a guest material(phosphorescent light-emitting material), were deposited byco-evaporation to have a weight ratio of 2mDBTBPDBq-II to PCBBiF and[Ir(dmdppr-P)₂(dibm)] of 0.75:0.25:0.1. The thickness was set to 40 nm.

Next, the electron-transport layer 914 was formed over thelight-emitting layer 913. The electron-transport layer 914 in thelight-emitting element 1 was formed in the following manner: 9mDBtBPNfprand 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline(abbreviation: NBphen) were sequentially deposited by evaporation tothicknesses of 30 nm and 15 nm, respectively. The electron-transportlayer 914 in the comparative light-emitting element 2 was formed in thefollowing manner: 2mDBTBPDBq-II and NBphen were sequentially depositedby evaporation to thicknesses of 30 nm and 15 nm, respectively.

Then, the electron-injection layer 915 was formed over theelectron-transport layer 914. The electron-injection layer 915 wasformed to a thickness of 1 nm by evaporation of lithium fluoride (LiF).

After that, the second electrode 903 was formed over theelectron-injection layer 915. The second electrode 903 was formed usingaluminum to a thickness of 200 nm by an evaporation method. In thisexample, the second electrode 903 functioned as a cathode.

Through the above steps, the light-emitting elements each including anEL layer between a pair of electrodes were formed over the substrate900. The hole-injection layer 911, the hole-transport layer 912, thelight-emitting layer 913, the electron-transport layer 914, and theelectron-injection layer 915 described above were functional layersforming the EL layer of one embodiment of the present invention.Furthermore, in all the evaporation steps in the above fabricationmethod, evaporation was performed by a resistance-heating method.

Each of the light-emitting elements fabricated as described above wassealed using another substrate (not illustrated) in such a manner thatthe substrate (not illustrated) with an ultraviolet curable sealant wasfixed to the substrate 900 in a glove box containing a nitrogenatmosphere, and the substrates were bonded to each other with thesealant attached to the periphery of the light-emitting element formedover the substrate 900. At the time of the sealing, the sealant wasirradiated with 365-nm ultraviolet light at 6 J/cm² to be solidified,and the sealant was heated at 80° C. for 1 hour to be stabilized.

<<Operation Characteristics of Light-Emitting Elements>>

Operation characteristics of the fabricated light-emitting elements weremeasured. Note that the measurement was performed at room temperature(in an atmosphere kept at 25° C.). As the results of the operationcharacteristics of the light-emitting elements, the currentdensity-luminance characteristics are shown in FIG. 12, thevoltage-luminance characteristics are shown in FIG. 13, theluminance-current efficiency characteristics are shown in FIG. 14, andthe voltage-current characteristics are shown in FIG. 15.

Table 2 shows initial values of main characteristics of thelight-emitting elements at around 1000 cd/m².

TABLE 2 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light-emitting 3.2 0.25 6.2(0.71, 0.29) 930 15 15 26 element 1 Comparative 3.7 0.29 7.2 (0.71,0.29) 1000 14 12 25 light-emitting element 2

The above results show that the light-emitting element 1 fabricated inthis example has high efficiency.

FIG. 16 shows emission spectra when current at a current density of 2.5mA/cm² was applied to the light-emitting element 1 and the comparativelight-emitting element 2. As shown in FIG. 16, the emission spectrum ofeach of the light-emitting element 1 and the comparative light-emittingelement 2 has a peak at around 640 nm that is probably derived fromlight emission of [Ir(dmdppr-P)₂(dibm)] contained in the light-emittinglayer 913.

Next, reliability tests were performed on the light-emitting element 1and the comparative light-emitting element 2. FIG. 17 shows results ofthe reliability tests. In FIG. 17, the vertical axis representsnormalized luminance (%) with an initial luminance of 100%, and thehorizontal axis represents driving time (h) of the elements. As thereliability tests, constant current driving tests at a constant currentdensity of 50 mA/cm² were performed.

The results of the reliability tests show that the light-emittingelement 1 has higher reliability than the comparative light-emittingelement 2. This is probably derived from a difference in molecularstructures between 9mDBtBPNfpr and 2mDBTBPDBq-II, that is, a differencebetween a naphthofuropyrazine skeleton and a dibenzoquinoxalineskeleton, thus showing robustness of a furopyrazine derivative of oneembodiment of the present invention. Accordingly, it is indicated thatthe use of 9mDBtBPNfpr (Structural Formula (100)), which is the organiccompound of one embodiment of the present invention, is effective inimproving the element characteristics of a light-emitting element.

Example 3

In this example, a light-emitting element 3 using 9mDBtBPNfpr(Structural Formula (100), Example 1) in its light-emitting layer wasfabricated as a light-emitting element of one embodiment of the presentinvention. The measured characteristic results of the light-emittingelement 3 will be described below.

Note that the first electrode 901 and the hole-injection layer 911 ofthe light-emitting element 3 were formed in the same manner as those ofthe light-emitting element 1 in Example 2.

The hole-transport layer 912 was formed over the hole-injection layer911 to a thickness of 20 nm by evaporation of4,4′-diphenyl-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine(abbreviation: PCBBi1BP).

The light-emitting layer 913 was formed over the hole-transport layer912 in the following manner: 9mDBtBPNfpr, PCBBiF, andbis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC](2,4-pentanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmpqn)₂(acac)]), which was used as a guest material(phosphorescent light-emitting material), were deposited byco-evaporation to have a weight ratio of 9mDBtBPNfpr to PCBBiF and[Ir(dmpqn)₂(acac)] of 0.8:0.2:0.1. The thickness was set to 40 nm.

The electron-transport layer 914 was formed over the light-emittinglayer 913 in the following manner: 9mDBtBPNfpr and NBphen weresequentially deposited by evaporation to thicknesses of 30 nm and 15 nm,respectively.

The electron-injection layer 915 and the second electrode 903 wereformed in the same manner as those of the light-emitting element 1 inExample 2; thus, the description thereof is omitted. Table 3 shows aspecific element structure of the light-emitting element 3. Chemicalformulae of materials used in this example are shown below.

TABLE 3 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode 901 911 912 913 914 915 903 Light- ITSO DBT3P-II:MoOxPCBBi1BP * 9mDBtBPNfpr NBphen LiF Al emitting (70 nm) (2:1, 70 nm) (20nm) (30 nm) (15 nm) (1 nm) (200 nm) element 3 *9mDBtBPNfpr:PCBBiF:[Ir(dmpqn)₂(acac)] (0.8:0.2:0.1, 40 nm)

<<Operation Characteristics of Light-Emitting Element 3>>

Operation characteristics of the fabricated light-emitting element 3were measured. Note that the measurement was performed at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 18, FIG. 19, FIG. 20, and FIG. 21 show the currentdensity-luminance characteristics, the voltage-luminancecharacteristics, the luminance-current efficiency characteristics, andthe voltage-current characteristics, respectively, of the light-emittingelement 3.

Table 4 shows initial values of main characteristics of thelight-emitting element 3 at around 1000 cd/m².

TABLE 4 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 2.9 0.20 4.9 (0.68,0.32) 970 20 21 21 emitting element 3

The above results show that the light-emitting element 3 fabricated inthis example has high efficiency.

FIG. 22 shows an emission spectrum when current at a current density of2.5 mA/cm² was applied to the light-emitting element 3. As shown in FIG.22, the emission spectrum of the light-emitting element has a peak ataround 626 nm that is probably derived from light emission of[Ir(dmpqn)₂(acac)] contained in the light-emitting layer 913.

Next, a reliability test was performed on the light-emitting element 3.FIG. 23 shows results of the reliability test. In FIG. 23, the verticalaxis represents normalized luminance (%) with an initial luminance of100%, and the horizontal axis represents driving time (h) of theelement. As the reliability test, a constant current driving test at aconstant current density of 75 mA/cm² was performed.

The results of the reliability test show that the light-emitting element3 has high reliability. This indicates that the use of 9mDBtBPNfpr(Structural Formula (100)), which is the organic compound of oneembodiment of the present invention, is effective in improving theelement characteristics of a light-emitting element.

Example 4

In this example, a light-emitting element 4 using 9mDBtBPNfpr(Structural Formula (100), Example 1) in its light-emitting layer wasfabricated as a light-emitting element of one embodiment of the presentinvention. The measured characteristic results of the light-emittingelement 4 will be described below.

Note that the first electrode 901 and the hole-injection layer 911 ofthe light-emitting element 4 were formed in the same manner as those ofthe light-emitting element 1 in Example 2.

The hole-transport layer 912 was formed over the hole-injection layer911 to a thickness of 20 nm by evaporation of PCBBiF.

The light-emitting layer 913 was formed over the hole-transport layer912 in the following manner: 9mDBtBPNfpr, PCBBiF, andbis{4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ²O,O′)iridium(III)(abbreviation: [Ir(dmdppr-m5CP)₂(dpm)]), which was used as a guestmaterial (phosphorescent light-emitting material), were deposited byco-evaporation to have a weight ratio of 9mDBtBPNfpr to PCBBiF and[Ir(dmdppr-m5CP)₂(dpm)] of 0.8:0.2:0.1. The thickness was set to 40 nm.

The electron-transport layer 914 was formed over the light-emittinglayer 913 in the following manner 9mDBtBPNfpr and NBphen weresequentially deposited by evaporation to thicknesses of 30 nm and 15 nm,respectively.

The electron-injection layer 915 and the second electrode 903 wereformed in the same manner as those of the light-emitting element 1 inExample 2; thus, the description thereof is omitted. Table 5 shows aspecific element structure of the light-emitting element 4. Chemicalformulae of materials used in this example are shown below.

TABLE 5 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode 901 911 912 913 914 915 903 Light- ITSO DBT3P-II:MoOxPCBBiF * 9mDBtBPNfpr NBphen LiF Al emitting (70 nm) (2:1, 75 nm) (20 nm)(30 nm) (15 nm) (1 nm) (200 nm) element 4 *9mDBtBPNfpr:PCBBiF:[Ir(dmdppr-m5CP)₂(dpm)] (0.8:0.2:0.1, 40 nm)

<<Operation Characteristics of Light-Emitting Element 4>>

Operation characteristics of the fabricated light-emitting element 4were measured. Note that the measurement was performed at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 24, FIG. 25, FIG. 26, and FIG. 27 show the currentdensity-luminance characteristics, the voltage-luminancecharacteristics, the luminance-current efficiency characteristics, andthe voltage-current characteristics, respectively, of the light-emittingelement 4.

Table 6 shows initial values of main characteristics of thelight-emitting element 4 at around 1000 cd/m².

TABLE 6 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 3.5 0.39 9.7 (0.71,0.29) 980 10 9.2 23 emitting element 4

The above results show that the light-emitting element 4 fabricated inthis example has high efficiency.

FIG. 28 shows an emission spectrum when current at a current density of2.5 mA/cm² was applied to the light-emitting element 4. As shown in FIG.28, the emission spectrum of the light-emitting element has a peak ataround 648 nm that is probably derived from light emission of[Ir(dmdppr-m5CP)₂(dpm)] contained in the light-emitting layer 913.

Next, a reliability test was performed on the light-emitting element 4.FIG. 29 shows results of the reliability test. In FIG. 29, the verticalaxis represents normalized luminance (%) with an initial luminance of100%, and the horizontal axis represents driving time (h) of theelement. As the reliability test, a constant current driving test at aconstant current density of 75 mA/cm² was performed.

The results of the reliability test show that the light-emitting element4 has high reliability. This indicates that the use of 9mDBtBPNfpr(Structural Formula (100)), which is the organic compound of oneembodiment of the present invention, is effective in improving theelement characteristics of a light-emitting element.

Example 5

In this example, a light-emitting element 5 using 9mDBtBPNfpr(Structural Formula (100), Example 1) in its light-emitting layer wasfabricated as a light-emitting element of one embodiment of the presentinvention. The measured characteristic results of the light-emittingelement 5 will be described below.

Table 7 shows a specific element structure of the light-emitting element5. In the table, APC represents an alloy of silver, palladium, andcopper (Ag—Pd—Cu). Refer to FIG. 11 for the stacked-layer structure ofthe light-emitting element. Note that the light-emitting element 5 alsoincluded a cap layer in contact with the second electrode 903. Chemicalformulae of materials used in this example are shown below.

TABLE 7 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode Cap layer 901 911 912 913 914 915 903 — Light- APC\ITSODBT3P-II:MoOx PCBBiF * 9mDBtBPNfpr NBphen LiF Ag:Mg DBT3P-II emitting(110 nm) (2:1, 70 nm) (15 nm) (30 nm) (20 nm) (1 nm) (25 nm) (70 nm)element 5 * 9mDBtBPNfpr:PCBBiF:[Ir(dmdppr-m5CP)₂(dpm)] (0.8:0.2:0.04, 40nm)

<<Operation Characteristics of Light-Emitting Element 5>>

Operation characteristics of the fabricated light-emitting element 5were measured. Note that the measurement was performed at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 30, FIG. 31, FIG. 32, and FIG. 33 show the currentdensity-luminance characteristics, the voltage-luminancecharacteristics, the luminance-current efficiency characteristics, andthe voltage-current characteristics, respectively, of the light-emittingelement 5.

Table 8 shows initial values of main characteristics of thelight-emitting element 5 at around 1000 cd/m².

TABLE 8 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 3.1 0.13 3.4 (0.70,0.30) 1100 33 34 37 emitting element 5

The above results show that the light-emitting element 5 fabricated inthis example has high efficiency.

FIG. 34 shows an emission spectrum when current at a current density of2.5 mA/cm² was applied to the light-emitting element 5. As shown in FIG.34, the emission spectrum of the light-emitting element has a peak ataround 635 nm that is probably derived from light emission of[Ir(dmdppr-m5CP)₂(dpm)] contained in the light-emitting layer 913.Accordingly, 9mDBtBPNfpr, the organic compound of one embodiment of thepresent invention, is a host material that is suitably used with aphosphorescent material that emits light with energy at a wavelengthlonger than or equal to that of red light.

Next, a reliability test was performed on the light-emitting element 5.FIG. 35 shows results of the reliability test. In FIG. 35, the verticalaxis represents normalized luminance (%) with an initial luminance of100%, and the horizontal axis represents driving time (h) of theelement. As the reliability test, a constant current driving test at aconstant current density of 12.5 mA/cm² was performed.

The results of the reliability test show that the light-emitting element5 has high reliability. This indicates that the use of 9mDBtBPNfpr(Structural Formula (100)), which is the organic compound of oneembodiment of the present invention, is effective in improving theelement characteristics of a light-emitting element.

Here, a top-emission panel formed by combination of the light-emittingelement 5 and light-emitting elements 6 and 7 having element structuresin Table 9 and operation characteristics in Table 10 was assumed. Then,simulation was performed under the following conditions: an apertureratio was 15% (5% for each of R, G, and B pixels), attenuation of lightby a circularly polarizing plate or the like was 60%, and a white colorat D65 and 300 cd/m² was displayed entirely.

TABLE 9 Hole- Light- Electron- First Hole-injection transport emittinginjection electrode layer layer layer Electron-transport layer layerSecond electrode Light- APC\ITO DBT3P-II:MoOx BPAFLP ** 2mDBTBPDBcp-IIBphen LiF Ag:Mg ITO emitting (110 nm) (1:0.5) (15 nm) (15 nm) (15 nm) (1nm) (1:0.1) (70 nm) element (25 nm) (25 nm) 6(G) Light- APC\ITOPCPPn:MoOx PCPPn *** cgDBCzPA NBphen LiF Ag:Mg ITO emitting (85 nm)(1:0.5) (15 nm) (5 nm) (15 nm) (1 nm) (1:0.1) (70 nm) element (37.5 nm)(25 nm) 7(B) ** 2mDBTBPDBq-II:PCBBiF:[Ir(tBuppm)₃] (0.7:0.3:0.06 (20nm)\0.8:0.2:0.06 (20 nm)) *** cgDBCzPA:1,6BnfAPrn-03 (1:0.03 (25 nm))

The chemical formulae of some of the materials used in thelight-emitting elements in Table 9 are shown below.

TABLE 10 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 2.7 0.04 1.1 (0.183,0.786) 1100 99 110 24 emitting element 6(G) Light- 3.3 1.20 29 (0.141,0.044) 1100 3.6 3.5 6.9 emitting element 7(B)

Table 11 shows some measurement results of the light-emitting elementsused in the simulation.

TABLE 11 Light- Panel Pixel Current Current Power emitting CIE luminanceluminance efficiency density Voltage consumption element x y (cd/m²)(cd/m²) (cd/A) (mA/cm²) (V) (mW/cm²) Light- 0.703 0.297 77 3864 30.312.8 3.75 2.39 emitting element 5(R) Light- 0.182 0.786 205 10257 95.410.8 3.40 1.83 emitting element 6(G) Light- 0.141 0.045 18 879 3.7 24.13.20 3.85 emitting element 7(B)

According to the simulation using the data in Table 11, the ratio of thearea of the panel formed by the combination of the light-emittingelements 5(R), 6(G), and 7(B) to the BT.2020 color gamut was 97% whenbeing calculated from the chromaticities (x,y) of the light-emittingelements on the CIE1976 chromaticity coordinates (u′,v′ chromaticitycoordinates).

Example 6 Synthesis Example 2

This example describes a method for synthesizing9-(9′-phenyl-3,3′-bi-9H-carbazol-9-yl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9PCCzNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(123) in Embodiment 1. The structure of 9PCCzNfpr is shown below.

Into a three-neck flask were put 0.94 g of9-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesis method isdescribed in Step 2 in Example 1, 1.69 g of9′-phenyl-3,3′-bi-9H-carbazole, and 37 mL of mesitylene, and the air inthe flask was replaced with nitrogen. The mixture in the flask wasdegassed by being stirred under reduced pressure, and then 1.23 g ofsodium tert-butoxide, 0.021 g oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and0.030 g of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl(abbreviation: S-Phos) were added thereto. The mixture was stirred at120° C. for 8 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was dissolved in toluene, and the mixture wasfiltered through a filter aid in which Celite, alumina, and Celite werestacked in this order and was recrystallized with a mixed solvent oftoluene and hexane, so that 0.85 g of a target yellow solid was obtainedin a yield of 36%.

By a train sublimation method, 0.84 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 350° C. under a pressure of 2.5 Pa with an argon gas flowrate of 10 mL/min. After the purification by sublimation, 0.64 g of atarget yellow solid was obtained in a yield of 76%. A synthesis schemeof the above synthesis method is shown in (b-1) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained by the above synthesis method are shown below.FIG. 36 is the ¹H-NMR chart. The results revealed that 9PCCzNfpr, theorganic compound represented by Structural Formula (123), was obtainedin this example.

¹H-NMR. δ (CDCl₃): 7.32-7.35 (m, 1H), 7.42-7.57 (m, 6H), 7.63-7.70 (m,5H), 7.80-7.90 (m, 4H), 8.09 (d, 2H), 8.14 (d, 2H), 8.27 (d, 2H), 8.49(d, 2H), 9.20 (d, 1H), 9.27 (s, 1H).

Example 7 Synthesis Example 3

This example describes a method for synthesizing9-[3-(9′-phenyl-3,3′-bi-9H-carbazol-9-yl)phenyl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mPCCzPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(125) in Embodiment 1. The structure of 9mPCCzPNfpr is shown below.

Step 1: Synthesis of9-(3-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine

Into a three-neck flask were put 2.12 g of9-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesis method isdescribed in Step 2 in Example 1, 1.41 g of 3-chlorophenylboronic acid,14 mL of a 2M potassium carbonate aqueous solution, 83 mL of toluene,and 8.3 mL of ethanol, and the air in the flask was replaced withnitrogen. The mixture in the flask was degassed by being stirred underreduced pressure, and then 0.19 g of palladium(II) acetate(abbreviation: Pd(OAc)₂) and 1.12 g oftris(2,6-dimethoxyphenyl)phosphine (abbreviation: P(2,6-MeOPh)₃) wereadded thereto. The mixture was stirred at 90° C. for 7.5 hours to bereacted.

After a predetermined time elapsed, the obtained mixture was subjectedto suction filtration and was washed with ethanol. Then, purification bysilica gel column chromatography using toluene as a developing solventwas performed, so that 1.97 g of a target pyrazine derivative (yellowishwhite powder) was obtained in a yield of 73%. A synthesis scheme of Step1 is shown in (c-1) below.

Step 2: Synthesis of 9mPCCzPNfpr

Next, into a three-neck flask were put 1.45 g of9-(3-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine obtained in Step1, 1.82 g of 9′-phenyl-3,3′-bi-9H-carbazole, and 22 mL of mesitylene,and the air in the flask was replaced with nitrogen. The mixture in theflask was degassed by being stirred under reduced pressure, and then0.85 g of sodium tert-butoxide, 0.025 g oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and0.036 g of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl(abbreviation: S-Phos) were added thereto. The mixture was stirred at150° C. for 7 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was dissolved in toluene, and the mixture wasfiltered through a filter aid in which Celite, alumina, and Celite werestacked in this order and was recrystallized with a mixed solvent oftoluene and hexane, so that 2.22 g of a target yellow solid was obtainedin a yield of 71%.

By a train sublimation method, 2.16 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 385° C. under a pressure of 2.6 Pa with an argon gas flowrate of 18 mL/min. After the purification by sublimation, 1.67 g of atarget yellow solid was obtained in a yield of 77%. A synthesis schemeof Step 2 is shown in (c-2) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained in Step 2 are shown below. FIG. 37 is the¹H-NMR chart. The results revealed that 9mPCCzPNfpr, the organiccompound represented by Structural Formula (125), was obtained in thisexample.

¹H-NMR. δ (CD₂Cl₂): 7.31-7.39 (m, 2H), 7.43-7.59 (m, 6H), 7.64-7.69 (m,6H), 7.78-7.88 (m, 6H), 8.09 (d, 1H), 8.15 (d, 1H), 8.26 (d, 1H), 8.30(d, 1H), 8.34 (d, 1H), 8.51-8.55 (m, 3H), 9.15 (d, 1H), 9.35 (s, 1H).

Example 8 Synthesis Example 4

This example describes a method for synthesizing9-[3-(9′-phenyl-2,3′-bi-9H-carbazol-9-yl)phenyl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mPCCzPNfpr-02), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(126) in Embodiment 1. The structure of 9mPCCzPNfpr-02 is shown below.

Into a three-neck flask were put 1.19 g of9-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesis method isdescribed in Step 2 in Example 1, 3.51 g of3-(9′-phenyl-2,3′-bi-9H-carbazol-9-yl)phenylboronic acid pinacol ester,6.0 mL of a 2M potassium carbonate aqueous solution, 60 mL of toluene,and 6 mL of ethanol, and the air in the flask was replaced withnitrogen. The mixture in the flask was degassed by being stirred underreduced pressure, and then 0.33 g ofbis(triphenylphosphine)palladium(II) dichloride (abbreviation:Pd(PPh₃)₂Cl₂) was added thereto. The mixture was stirred at 90° C. for16 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was dissolved in toluene, and the mixture wasfiltered through a filter aid in which Celite, alumina, and Celite werestacked in this order and was recrystallized with a mixed solvent oftoluene and hexane, so that 3.01 g of a target yellow solid was obtainedin a yield of 90%.

By a train sublimation method, 3.00 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 380° C. under a pressure of 2.7 Pa with an argon gas flowrate of 16 mL/min. After the purification by sublimation, 2.47 g of atarget yellow solid was obtained in a yield of 82%. A synthesis schemeis shown in (d-1) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained above are shown below. FIG. 38 is the ¹H-NMRchart. The results revealed that 9mPCCzPNfpr-02, the organic compoundrepresented by Structural Formula (126), was obtained in this example.

¹H-NMR. δ (CD₂Cl₂): 7.22-7.25 (m, 1H), 7.34-7.42 (m, 3H), 7.46-7.49 (m,3H), 7.55-7.66 (m, 6H), 7.72-7.88 (m, 7H), 8.07 (d, 1H), 8.13 (d, 1H),8.19-8.22 (m, 2H), 8.28 (d, 1H), 8.33 (d, 1H), 8.46 (s, 1H), 8.54 (s,1H), 9.14 (d, 1H), 9.34 (s, 1H).

Example 9 Synthesis Example 5

This example describes a method for synthesizing10-[(3′-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 10mDBtBPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(133) in Embodiment 1. The structure of 10mDBtBPNfpr is shown below.

Step 1: Synthesis of5-chloro-3-(2-methoxynaphthalen-1-yl)pyrazin-2-amine

First, into a three-neck flask equipped with a reflux pipe were put 5.01g of 3-bromo-5-chloropyrazin-2-amine, 6.04 g of2-methoxynaphthalene-1-boronic acid, 5.32 g of potassium fluoride, and86 mL of dehydrated tetrahydrofuran, and the air in the flask wasreplaced with nitrogen. The mixture in the flask was degassed by beingstirred under reduced pressure, and then 0.44 g oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃) and3.4 mL of tri-tert-butylphosphine (abbreviation: P(tBu)₃) were addedthereto. The mixture was stirred at 80° C. for 22 hours to be reacted.

After a predetermined time elapsed, the obtained mixture was subjectedto suction filtration and the filtrate was concentrated. Then,purification by silica gel column chromatography using a developingsolvent (toluene:ethyl acetate=10:1) was performed, so that 5.69 g of atarget pyrazine derivative (yellowish white powder) was obtained in ayield of 83%. A synthesis scheme of Step 1 is shown in (e-1) below.

Step 2: Synthesis of 10-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine

Next, into a three-neck flask were put 5.69 g of5-chloro-3-(2-methoxynaphthalen-1-yl)pyrazin-2-amine obtained in Step 1,150 mL of dehydrated tetrahydrofuran, and 150 mL of a glacial aceticacid, and the air in the flask was replaced with nitrogen. After theflask was cooled down to −10° C., 7.1 mL of tert-butyl nitrite wasdripped, and the mixture was stirred at −10° C. for 1 hour and at 0° C.for 3.5 hours. After a predetermined time elapsed, 1 L of water wasadded to the obtained suspension and suction filtration was performed,so that 4.06 g of a target pyrazine derivative (yellowish white powder)was obtained in a yield of 81%. A synthesis scheme of Step 2 is shown in(e-2) below.

Step 3: Synthesis of 10mDBtBPNfpr

Into a three-neck flask were put 1.18 g of10-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine obtained in Step 2, 2.75g of 3′-(4-dibenzothiophene)-1,1′-biphenyl-3-boronic acid, 7.5 mL of a2M potassium carbonate aqueous solution, 60 mL of toluene, and 6 mL ofethanol, and the air in the flask was replaced with nitrogen. Themixture in the flask was degassed by being stirred under reducedpressure, and then 0.66 g of bis(triphenylphosphine)palladium(II)dichloride (abbreviation: Pd(PPh₃)₂Cl₂) was added thereto. The mixturewas stirred at 90° C. for 22.5 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was dissolved in toluene, and the mixture wasfiltered through a filter aid in which Celite, alumina, and Celite werestacked in this order and was recrystallized with a mixed solvent oftoluene and hexane, so that 2.27 g of a target white solid was obtainedin a yield of 87%.

By a train sublimation method, 2.24 g of the obtained white solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 310° C. under a pressure of 2.3 Pa with an argon gas flowrate of 16 mL/min. After the purification by sublimation, 1.69 g of atarget white solid was obtained in a yield of 75%. A synthesis scheme ofStep 3 is shown in (e-3) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe white solid obtained in Step 3 are shown below. FIG. 39 is the¹H-NMR chart. The results revealed that 10mDBtBPNfpr, the organiccompound represented by Structural Formula (133), was obtained in thisexample.

¹H-NMR. δ (CDCl₃): 7.43 (t, 1H), 7.48 (t, 1H), 7.59-7.62 (m, 3H),7.68-7.86 (m, 8H), 8.05 (d, 1H), 8.12 (d, 1H), 8.18 (s, 1H), 8.20-8.24(m, 3H), 8.55 (s, 1H), 8.92 (s, 1H), 9.31 (d, 1H).

Example 10 Synthesis Example 6

This example describes a method for synthesizing10-(9′-phenyl-3,3′-bi-9H-carbazol-9-yl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 10PCCzNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(156) in Embodiment 1. The structure of 10PCCzNfpr is shown below.

Into a three-neck flask were put 1.80 g of10-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesis method isdescribed in Step 2 in Example 9, 3.10 g of9′-phenyl-3,3′-bi-9H-carbazole, and 71 mL of mesitylene, and the air inthe flask was replaced with nitrogen. The mixture in the flask wasdegassed by being stirred under reduced pressure, and then 2.21 g ofsodium tert-butoxide, 0.041 g oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and0.061 g of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl(abbreviation: S-Phos) were added thereto. The mixture was stirred at120° C. for 2 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was dissolved in toluene, and the mixture wasfiltered through a filter aid in which Celite, alumina, and Celite werestacked in this order and was recrystallized with a mixed solvent oftoluene and hexane, so that 3.47 g of a target orange solid was obtainedin a yield of 78%.

By a train sublimation method, 3.42 g of the obtained orange solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 350° C. under a pressure of 2.4 Pa with an argon gas flowrate of 16 mL/min. After the purification by sublimation, 2.86 g of atarget orange solid was obtained in a yield of 84%. A synthesis schemeof Step 3 is shown in (f-1) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe orange solid obtained by the above synthesis method are shown below.FIG. 40 is the ¹H-NMR chart. The results revealed that 10PCCzNfpr, theorganic compound represented by Structural Formula (156), was obtainedin this example.

¹H-NMR. δ (CDCl₃): 7.32-7.35 (m, 1H), 7.43-7.57 (m, 6H), 7.63-7.68 (m,5H), 7.79-7.84 (m, 2H), 7.89-7.91 (m, 2H), 8.01 (d, 1H), 8.07-8.09 (m,2H), 8.18 (d, 1H), 8.27 (d, 1H), 8.30 (d, 1H), 8.51 (s, 2H), 8.85 (s,1H), 9.16 (d, 1H).

Example 11 Synthesis Example 7

This example describes a method for synthesizing12-[(3′-dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9′,10′:4,5]furo[2,3-b]pyrazine(abbreviation: 12mDBtBPPnfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(208) in Embodiment 1. The structure of 12mDBtBPPnfpr is shown below.

Step 1: Synthesis of 9-methoxyphenanthrene

First, into a three-neck flask equipped with a reflux pipe were put 4.02g of 9-bromo-phenanthrene, 7.80 g of cesium carbonate, 16 mL of toluene,and 16 mL of methanol, and the air in the flask was replaced withnitrogen. The mixture in the flask was degassed by being stirred underreduced pressure, and then 0.11 g of palladium(II) acetate(abbreviation: Pd(OAc)₂) and 0.41 g of2-di-tert-butylphosphino-2′,4′,6′-triisopropylbiphenyl (abbreviation:tBuXPhos) were added thereto. The mixture was stirred at 80° C. for 17hours to be reacted.

After a predetermined time elapsed, the obtained mixture was subjectedto suction filtration and the filtrate was concentrated. Then,purification by silica gel column chromatography using a developingsolvent (toluene:hexane=1:3) was performed, so that 2.41 g of a targetwhite powder was obtained in a yield of 74%. A synthesis scheme of Step1 is shown in (g-1) below.

Step 2: Synthesis of 9-bromo-10-methoxyphenanthrene

Next, into a conical flask were put 2.75 g of 9-methoxyphenanthreneobtained in Step 1, 0.18 mL of diisopropylamine, 150 mL of dehydrateddichloromethane, and 2.52 g of N-bromosuccinimide (abbreviation: NBS),and the mixture was stirred at room temperature for 18 hours. After apredetermined time elapsed, the mixture was washed with water and anaqueous solution of sodium thiosulfate, and then concentrated. Then,purification by silica gel column chromatography using a developingsolvent (hexane:ethyl acetate=5:1) was performed, so that 2.46 g of atarget yellowish white powder was obtained in a yield of 65%. Asynthesis scheme of Step 2 is shown in (g-2) below.

Step 3: Synthesis of 10-methoxyphenanthrene-9-boronic acid

Next, into a three-neck flask were put 8.49 g of9-bromo-10-methoxyphenanthrene obtained in Step 2 and 250 mL ofdehydrated THF, and the air in the flask was replaced with nitrogen.After the flask was cooled down to −78° C., 22 mL of a 1.6M hexanesolution of n-butyllithium was added, and the mixture was stirred at−78° C. for 3 hours. Then, 5.7 mL of tetramethylethylenediamine and 4.3mL of trimethyl borate were added, and the mixture was stirred at roomtemperature for 18 hours to be reacted.

After a predetermined time elapsed, 50 mL of 1M hydrochloric acid wasadded, and the mixture was stirred at room temperature for 1 hour. Then,extraction with toluene was performed, so that 2.87 g of a target paleorange powder was obtained in a yield of 39%. A synthesis scheme of Step3 is shown in (g-3) below.

Step 4: Synthesis of5-chloro-3-(10-methoxyphenanthren-9-yl)pyrazin-2-amine

Next, into a three-neck flask equipped with a reflux pipe were put 3.69g of 10-methoxyphenanthrene-9-boronic acid obtained in Step 3, 3.02 g of3-bromo-5-chloropyrazin-2-amine, 70 mL of toluene, and 35 mL of a 2Msodium carbonate aqueous solution, and the air in the flask was replacedwith nitrogen. The mixture in the flask was degassed by being stirredunder reduced pressure, and then 0.16 g oftetrakis(triphenylphosphine)palladium(0) (abbreviation: Pd(PPh₃)₄) wasadded thereto. The mixture was stirred at 110° C. for 7.5 hours to bereacted.

After a predetermined time elapsed, extraction with toluene wasperformed. Then, purification by flash column chromatography using adeveloping solvent (dichloromethane:ethyl acetate=50:1) was performed,so that 3.00 g of a target pyrazine derivative (yellowish white powder)was obtained in a yield of 62%. A synthesis scheme of Step 4 is shown in(g-4) below.

Step 5: Synthesis of 12-chlorophenanthro[9′,10′:4,5]furo[2,3-b]pyrazine

Next, into a three-neck flask were put 2.92 g of5-chloro-3-(10-methoxyphenanthren-9-yl)pyrazin-2-amine obtained in Step4, 60 mL of dehydrated tetrahydrofuran, and 60 mL of a glacial aceticacid, and the air in the flask was replaced with nitrogen. After theflask was cooled down to −10° C., 3.1 mL of tert-butyl nitrite wasdripped, and the mixture was stirred at −10° C. for 1 hour and at 0° C.for 22 hours.

After a predetermined time elapsed, 200 mL of water was added to theobtained suspension and suction filtration was performed, so that 2.06 gof a target pyrazine derivative (yellowish white powder) was obtained ina yield of 80%. A synthesis scheme of Step 5 is shown in (g-5) below.

Step 6: Synthesis of12-(3-chlorophenyl)phenanthro[9′,10′:4,5]furo[2,3-b]pyrazine

Next, into a three-neck flask were put 1.02 g of12-chlorophenanthro[9′,10′:4,5]furo[2,3-b]pyrazine obtained in Step 5,0.56 g of 3-chlorophenylboronic acid, 5 mL of a 2M potassium carbonateaqueous solution, 33 mL of toluene, and 3.3 mL of ethanol, and the airin the flask was replaced with nitrogen. The mixture in the flask wasdegassed by being stirred under reduced pressure, and then 0.074 g ofpalladium(II) acetate (abbreviation: Pd(OAc)₂) and 0.44 g oftris(2,6-dimethoxyphenyl)phosphine (abbreviation: P(2,6-MeOPh)₃) wereadded thereto. The mixture was stirred at 90° C. for 5.5 hours to bereacted.

After a predetermined time elapsed, the obtained mixture was subjectedto suction filtration and the filtrate was concentrated. Then,purification by silica gel column chromatography using toluene as adeveloping solvent was performed, so that 0.87 g of a target pyrazinederivative (white powder) was obtained in a yield of 70%. A synthesisscheme of Step 6 is shown in (g-6) below.

Step 7: Synthesis of 12mDBtBPPnfpr

Next, into a three-neck flask were put 0.85 g of12-(3-chlorophenyl)phenanthro[9′,10′:4,5]furo[2,3-b]pyrazine obtained inStep 6, 0.73 g of 3-(4-dibenzothiophene)phenylboronic acid, 1.41 g oftripotassium phosphate, 0.49 g of tert-butyl alcohol, and 18 mL ofdiethylene glycol dimethyl ether (abbreviation: diglyme), and the air inthe flask was replaced with nitrogen. The mixture in the flask wasdegassed by being stirred under reduced pressure, and then 9.8 mg ofpalladium(II) acetate (abbreviation: Pd(OAc)₂) and 32 mg ofdi(1-adamantyl)-n-butylphosphine (abbreviation: CataCXium A) were addedthereto. The mixture was stirred at 140° C. for 11.5 hours to bereacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was dissolved in toluene, and the mixture wasfiltered through a filter aid in which Celite, alumina, and Celite werestacked in this order and was recrystallized with toluene, so that 0.74g of a target white solid was obtained in a yield of 55%.

By a train sublimation method, 0.73 g of the obtained white solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 330° C. under a pressure of 2.6 Pa with an argon gas flowrate of 11 mL/min. After the purification by sublimation, 0.49 g of atarget white solid was obtained in a yield of 67%. A synthesis scheme ofStep 7 is shown in (g-7) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe white solid obtained in Step 7 are shown below. FIG. 41 is the¹H-NMR chart. The results revealed that 12mDBtBPPnfpr, the organiccompound represented by Structural Formula (208), was obtained in thisexample.

¹H-NMR. δ (CD₂Cl₂): 7.45 (t, 1H), 7.50 (t, 1H), 7.62-7.66 (m, 2H),7.70-7.89 (m, 10H), 8.21-8.28 (m, 4H), 8.58-8.61 (m, 2H), 8.80 (d, 1H),8.84 (d, 1H), 8.94 (s, 1H), 9.37 (d, 1H).

Example 12 Synthesis Example 8

This example describes a method for synthesizing9-[4-(9′-phenyl-3,3′-bi-9H-carbazol-9-yl)phenyl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9pPCCzPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(238) in Embodiment 1. The structure of 9pPCCzPNfpr is shown below.

Step 1: Synthesis of9-(4-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine

Into a three-neck flask were put 4.10 g of9-chloronaphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesis method isdescribed in Step 2 in Example 1, 2.80 g of 4-chlorophenylboronic acid,27 mL of a 2M potassium carbonate aqueous solution, 160 mL of toluene,and 16 mL of ethanol, and the air in the flask was replaced withnitrogen. The mixture in the flask was degassed by being stirred underreduced pressure, and then 0.36 g of palladium(II) acetate(abbreviation: Pd(OAc)₂) and 2.08 g oftris(2,6-dimethoxyphenyl)phosphine (abbreviation: P(2,6-MeOPh)₃) wereadded thereto. The mixture was stirred at 90° C. for 7 hours to bereacted.

After a predetermined time elapsed, the obtained mixture was subjectedto suction filtration and was washed with ethanol. Then, purification bysilica gel column chromatography using toluene as a developing solventwas performed, so that 2.81 g of a target pyrazine derivative (yellowishwhite powder) was obtained in a yield of 52%. A synthesis scheme of Step1 is shown in (h-1) below.

Step 2: Synthesis of 9pPCCzPNfpr

Next, into a three-neck flask were put 1.39 g of9-(4-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine obtained in Step1, 1.72 g of 9′-phenyl-3,3′-bi-9H-carbazole, and 21 mL of mesitylene,and the air in the flask was replaced with nitrogen. The mixture in theflask was degassed by being stirred under reduced pressure, and then0.81 g of sodium tert-butoxide, 0.024 g oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and0.034 g of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl(abbreviation: S-Phos) were added thereto. The mixture was stirred at150° C. for 6 hours to be reacted.

After a predetermined time elapsed, the reaction solution was subjectedto extraction with toluene. The solid obtained by concentrating theextract solution was purified by silica gel column chromatography usingtoluene as a developing solvent, and then recrystallized with toluenethree times, so that 1.84 g of a target yellow solid was obtained in ayield of 62%.

By a train sublimation method, 1.81 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 380° C. under a pressure of 2.7 Pa with an argon gas flowrate of 18 mL/min. After the purification by sublimation, 1.35 g of atarget yellow solid was obtained in a yield of 75%. A synthesis schemeof Step 2 is shown in (h-2) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained in Step 2 are shown below. FIG. 42 is the¹H-NMR chart. The results revealed that 9pPCCzPNfpr, the organiccompound represented by Structural Formula (238), was obtained in thisexample.

¹H-NMR. δ (CD₂Cl₂): 7.32-7.39 (m, 2H), 7.44-7.56 (m, 5H), 7.61 (d, 1H),7.64-7.69 (m, 6H), 7.83-7.91 (m, 6H), 8.11 (d, 1H), 8.17 (d, 1H), 8.28(d, 2H), 8.49-8.53 (m, 4H), 9.18 (d, 1H), 9.40 (s, 1H).

Example 13 Synthesis Example 9

This example describes a method for synthesizing9-[4-(9′-phenyl-2,3′-bi-9H-carbazol-9-yl)phenyl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9pPCCzPNfpr-02), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(239) in Embodiment 1. The structure of 9pPCCzPNfpr-02 is shown below.

Into a three-neck flask were put 1.76 g of9-(4-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesismethod is described in Step 1 in Example 12, 2.22 g of9′-phenyl-2,3′-bi-9H-carbazole, and 27 mL of mesitylene, and the air inthe flask was replaced with nitrogen. The mixture in the flask wasdegassed by being stirred under reduced pressure, and then 1.09 g ofsodium tert-butoxide, 0.031 g oftris(dibenzylideneacetone)dipalladium(0) (abbreviation: Pd₂(dba)₃), and0.045 g of 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl(abbreviation: S-Phos) were added thereto. The mixture was stirred at150° C. for 6 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and the residue was washed with waterand ethanol. The obtained solid was purified by silica gel columnchromatography using toluene as a developing solvent, and thenrecrystallized with a mixed solvent of toluene and hexane, so that 1.95g of a target yellow solid was obtained in a yield of 52%.

By a train sublimation method, 1.94 g of the obtained yellow solid waspurified by sublimation. In the purification by sublimation, the solidwas heated at 380° C. under a pressure of 2.7 Pa with an argon gas flowrate of 18 mL/min. After the purification by sublimation, 1.62 g of atarget yellow solid was obtained in a yield of 84%. A synthesis schemeis shown in (i-1) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained above are shown below. FIG. 43 is the ¹H-NMRchart. The results revealed that 9pPCCzPNfpr-02, the organic compoundrepresented by Structural Formula (239), was obtained in this example.

¹H-NMR. δ (CD₂Cl₂): 7.28-7.31 (m, 1H), 7.36 (t, 1H), 7.40-7.44 (m, 2H),7.46-7.51 (m, 3H), 7.57-7.69 (m, 6H), 7.74 (d, 1H), 8.78 (d, 1H), 7.84(t, 1H), 7.81-7.88 (m, 4H), 8.10 (d, 1H), 8.16 (d, 1H), 8.22 (d, 2H),8.28 (d, 1H), 8.46 (s, 1H), 8.50 (d, 2H), 9.17 (d, 1H), 9.38 (s, 1H).

Example 14 Synthesis Example 10

This example describes a method for synthesizing9-[3′-(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mBnfBPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(244) in Embodiment 1. The structure of 9mBnfBPNfpr is shown below.

Into a three-neck flask were put 1.28 g of9-(3-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesismethod is described in Step 1 in Example 7, 2.26 g of3-(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)phenylboronic acid pinacolester, 2.53 g of tripotassium phosphate, 0.89 g of tert-butyl alcohol,and 32 mL of diethylene glycol dimethyl ether (abbreviation: diglyme),and the air in the flask was replaced with nitrogen. The mixture in theflask was degassed by being stirred under reduced pressure, and then 8.8mg of palladium(II) acetate (abbreviation: Pd(OAc)₂) and 28 mg ofdi(1-adamantyl)-n-butylphosphine (abbreviation: CataCXium A) were addedthereto. The mixture was stirred at 140° C. for 8.5 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was purified by silica gel column chromatographyusing toluene as a developing solvent, and then recrystallized withtoluene, so that 0.66 g of a target yellow solid was obtained in a yieldof 25%. A synthesis scheme is shown in (j-1) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellow solid obtained above are shown below. FIG. 44 is the ¹H-NMRchart. The results revealed that 9mBnfBPNfpr, the organic compoundrepresented by Structural Formula (244), was obtained in this example.

¹H-NMR. δ (CD₂Cl₂): 7.24-7.28 (m, 3H), 7.61-7.72 (m, 5H), 7.78-7.87 (m,6H), 7.98-8.00 (m, 3H), 8.08 (d, 1H), 8.11-8.15 (m, 3H), 8.25 (d, 1H),8.48 (s, 1H), 8.51-8.53 (m, 2H), 8.75 (d, 1H), 9.15 (d, 1H), 9.32 (s,1H).

Example 15 Synthesis Example 11

This example describes a method for synthesizing9-[3′-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mDBtBPNfpr-02), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(245) in Embodiment 1. The structure of 9mDBtBPNfpr-02 is shown below.

Into a three-neck flask were put 1.19 g of9-(3-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesismethod is described in Step 1 in Example 7, 1.97 g of3-(6-phenyldibenzothiophen-4-yl)phenylboronic acid pinacol ester, 2.29 gof tripotassium phosphate, 0.82 g of tert-butyl alcohol, and 29 mL ofdiethylene glycol dimethyl ether (abbreviation: diglyme), and the air inthe flask was replaced with nitrogen. The mixture in the flask wasdegassed by being stirred under reduced pressure, and then 16 mg ofpalladium(II) acetate (abbreviation: Pd(OAc)₂) and 52 mg ofdi(1-adamantyl)-n-butylphosphine (abbreviation: CataCXium A) were addedthereto. The mixture was stirred at 140° C. for 15 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was purified by silica gel column chromatographyusing toluene as a developing solvent, and then recrystallized withtoluene, so that 1.17 g of a target yellowish white solid was obtainedin a yield of 52%. A synthesis scheme is shown in (k-1) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellowish white solid obtained above are shown below. FIG. 45 is the¹H-NMR chart. The results revealed that 9mDBtBPNfpr-02, the organiccompound represented by Structural Formula (245), was obtained in thisexample.

¹H-NMR. δ (CD₂Cl₂): 7.39 (t, 1H), 7.47-7.51 (m, 3H), 7.58-7.67 (m, 6H),7.73 (d, 2H), 7.78-7.85 (m, 5H), 8.02 (s, 1H), 8.06 (d, 1H), 8.10 (d,1H), 8.18 (d, 1H), 8.23 (t, 2H), 8.49 (s, 1H), 9.17 (d, 1H), 9.30 (s,1H).

Example 16 Synthesis Example 12

This example describes a method for synthesizing9-{3-[6-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenyl}naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mFDBtPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(246) in Embodiment 1. The structure of 9mFDBtPNfpr is shown below.

Into a three-neck flask were put 1.01 g of9-(3-chlorophenyl)naphtho[1′,2′:4,5]furo[2,3-b]pyrazine whose synthesismethod is described in Step 1 in Example 7, 1.46 g of3-[6-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenylboronic acid,1.89 g of tripotassium phosphate, 0.67 g of tert-butyl alcohol, and 24mL of diethylene glycol dimethyl ether (abbreviation: diglyme), and theair in the flask was replaced with nitrogen. The mixture in the flaskwas degassed by being stirred under reduced pressure, and then 27 mg ofpalladium(II) acetate (abbreviation: Pd(OAc)₂) and 88 mg ofdi(1-adamantyl)-n-butylphosphine (abbreviation: CataCXium A) were addedthereto. The mixture was stirred at 140° C. for 30 hours to be reacted.

After a predetermined time elapsed, the obtained suspension wassubjected to suction filtration and was washed with water and ethanol.The obtained solid was purified by silica gel column chromatographyusing toluene as a developing solvent, and then recrystallized with amixed solvent of toluene and hexane, so that 0.75 g of a targetyellowish white solid was obtained in a yield of 37%. A synthesis schemeis shown in (l-1) below.

Analysis results by nuclear magnetic resonance (¹H-NMR) spectroscopy ofthe yellowish white solid obtained above are shown below. FIG. 46 is the¹H-NMR chart. The results revealed that 9mFDBtPNfpr, the organiccompound represented by Structural Formula (246), was obtained in thisexample.

¹H-NMR. δ (CD₂Cl₂): 1.47 (s, 6H), 7.27-7.32 (m, 2H), 7.38 (d, 1H),7.61-7.76 (m, 8H), 7.79-7.85 (m, 4H), 7.89 (d, 1H), 8.08 (d, 1H), 8.13(d, 1H), 8.24-8.31 (m, 3H), 8.59 (s, 1H), 9.14 (d, 1H), 9.31 (s, 1H).

Example 17 Synthesis Example 13

This example describes a method for synthesizing11-(3-naphtho[1′,2′:4,5]furo[2,3-b]pyrazin-9-yl-phenyl)-12-phenylindolo[2,3-a]carbazole(abbreviation: 9mIcz(II)PNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(247) in Embodiment 1. The structure of 9mIcz(II)PNfpr is shown below.

A synthesis method of 9mIcz(II)PNfpr is shown by a synthesis scheme(m-1) below.

Example 18 Synthesis Example 14

This example describes a method for synthesizing3-naphtho[1′,2′:4,5]furo[2,3-b]pyrazin-9-yl-N,N-diphenylbenzenamine(abbreviation: 9mTPANfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(248) in Embodiment 1. The structure of 9mTPANfpr is shown below.

A synthesis method of 9mTPANfpr is shown by a synthesis scheme (n-1)below.

Example 19

In this example, a light-emitting element 8 using 10mDBtBPNfpr(Structural Formula (133), Example 9) in its light-emitting layer wasfabricated as a light-emitting element of one embodiment of the presentinvention. The measured characteristic results of the light-emittingelement 8 will be described below.

The element structure of the light-emitting element 8 fabricated in thisexample was similar to the element structure described in Example 2 withreference to FIG. 11. Table 12 shows specific structures of layers inthe element structure. Chemical formulae of materials used in thisexample are shown below.

TABLE 12 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode 901 911 912 913 914 915 903 Light- ITSO DBT3P-II:MoOxPCBBi1BP * 10mDBtBPNfpr NBphen LiF Al emitting (70 nm) (2:1, 75 nm) (20nm) (30 nm) (15 nm) (1 nm) (200 nm) element 8 *10mDBtBPNfpr:PCBBiF:[Ir(dmpqn)₂(acac)] (0.75:0.25:0.1, 40 nm)

<<Operation Characteristics of Light-Emitting Element 8>>

Operation characteristics of the fabricated light-emitting element 8were measured. Note that the measurement was performed at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 47, FIG. 48, FIG. 49, and FIG. 50 show the currentdensity-luminance characteristics, the voltage-luminancecharacteristics, the luminance-current efficiency characteristics, andthe voltage-current characteristics, respectively, of the light-emittingelement 8.

Table 13 shows initial values of main characteristics of thelight-emitting element 8 at around 1000 cd/m².

TABLE 13 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 3.4 0.21 5.1 (0.68,0.32) 950 18 17 19 emitting element 8

FIG. 51 shows an emission spectrum when current at a current density of2.5 mA/cm² was applied to the light-emitting element 8. As shown in FIG.51, the emission spectrum of the light-emitting element has a peak ataround 626 nm that is probably derived from light emission of[Ir(dmpqn)₂(acac)] contained in the light-emitting layer 913.

Next, a reliability test was performed on the light-emitting element 8.FIG. 52 shows results of the reliability test. In FIG. 52, the verticalaxis represents normalized luminance (%) with an initial luminance of100%, and the horizontal axis represents driving time (h) of theelement. As the reliability test, a constant current driving test at aconstant current density of 75 mA/cm² was performed.

The results of the reliability test show that the light-emitting element8 including 10mDBtBPNfpr, which is the organic compound of oneembodiment of the present invention, has high reliability. Thisindicates that the use of the organic compound of one embodiment of thepresent invention is effective in improving the reliability of alight-emitting element.

Example 20

In this example, a light-emitting element 9 using 12mDBtBPPnfpr(Structural Formula (208), Example 11) in its light-emitting layer wasfabricated as a light-emitting element of one embodiment of the presentinvention. The measured characteristic results of the light-emittingelement 9 will be described below.

The element structure of the light-emitting element 9 fabricated in thisexample was similar to the element structure described in Example 2 withreference to FIG. 11. Table 14 shows specific structures of layers inthe element structure. Chemical formulae of materials used in thisexample are shown below.

TABLE 14 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode 901 911 912 913 914 915 903 Light- ITSO DBT3P-II:MoOxPCBBi1BP * 12mDBtBPPnfpr NBphen LiF Al emitting (70 nm) (2:1, 70 nm) (20nm) (30 nm) (15 nm) (1 nm) (200 nm) element 9 *12mDBtBPPnfpr:PCBBiF:[Ir(dmpqn)₂(acac)] (0.75:0.25:0.1, 40 nm)

<<Operation Characteristics of Light-Emitting Element 9>>

Operation characteristics of the fabricated light-emitting element 9were measured. Note that the measurement was performed at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 53, FIG. 54, FIG. 55, and FIG. 56 show the currentdensity-luminance characteristics, the voltage-luminancecharacteristics, the luminance-current efficiency characteristics, andthe voltage-current characteristics, respectively, of the light-emittingelement 9.

Table 15 shows initial values of main characteristics of thelight-emitting element 9 at around 1000 cd/m².

TABLE 15 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 3.6 0.28 7.0 (0.68,0.32) 1100 15 13 17 emitting element 9

FIG. 57 shows an emission spectrum when current at a current density of2.5 mA/cm² was applied to the light-emitting element 9. As shown in FIG.57, the emission spectrum of the light-emitting element has a peak ataround 626 nm that is probably derived from light emission of[Ir(dmpqn)₂(acac)] contained in the light-emitting layer 913.

Next, a reliability test was performed on the light-emitting element 9.FIG. 58 shows results of the reliability test. In FIG. 58, the verticalaxis represents normalized luminance (%) with an initial luminance of100%, and the horizontal axis represents driving time (h) of theelement. As the reliability test, a constant current driving test at aconstant current density of 75 mA/cm² was performed.

The results of the reliability test show that the light-emitting element9 including 12mDBtBPPnfpr, which is the organic compound of oneembodiment of the present invention, has high reliability. Thisindicates that the use of the organic compound of one embodiment of thepresent invention is effective in improving the reliability of alight-emitting element.

Example 21

In this example, light-emitting elements 10 to 15 were fabricated aslight-emitting elements of embodiments of the present invention. Thelight-emitting element 10 was fabricated using 9PCCzNfpr (StructuralFormula (123), Example 6) in its light-emitting layer. Thelight-emitting element 11 was fabricated using 10PCCzNfpr (StructuralFormula (156), Example 10) in its light-emitting layer. Thelight-emitting element 12 was fabricated using 9mPCCzPNfpr (StructuralFormula (125), Example 7) in its light-emitting layer. Thelight-emitting element 13 was fabricated using 9mPCCzPNfpr-02(Structural Formula (126), Example 8) in its light-emitting layer. Thelight-emitting element 14 was fabricated using 9pPCCzPNfpr (StructuralFormula (238), Example 12) in its light-emitting layer. Thelight-emitting element 15 was fabricated using 9pPCCzPNfpr-02(Structural Formula (239), Example 13) in its light-emitting layer. Themeasured characteristic results of the light-emitting elements 10 to 15will be described below.

The element structures of the light-emitting elements 10 to 15fabricated in this example were similar to the element structure of thelight-emitting element 3 described in Example 3. Table 16 shows specificstructures of layers in the element structures. Chemical formulae ofmaterials used in this example are shown below.

TABLE 16 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode 901 911 912 913 914 915 903 Light- ITSO DBT3P-II:MoOxPCBBi1BP * 9PCCzNfpr NBphen LiF Al emitting (70 nm) (2:1, 70 nm) (20 nm)(30 nm) (15 nm) (1 nm) (200 nm) element 10 Light- ITSO DBT3P-II:MoOxPCBBi1BP ** 10PCCzNfpr NBphen LiF Al emitting (70 nm) (2:1, 70 nm) (20nm) (30 nm) (15 nm) (1 nm) (200 nm) element 11 Light- ITSO DBT3P-II:MoOxPCBBi1BP *** 9mPCCzPNfpr NBphen LiF Al emitting (70 nm) (2:1, 70 nm) (20nm) (30 nm) (15 nm) (1 nm) (200 nm) element 12 Light- ITSO DBT3P-II:MoOxPCBBi1BP **** 9mPCCzPNfpr-02 NBphen LiF Al emitting (70 nm) (2:1, 70 nm)(20 nm) (30 nm) (15 nm) (1 nm) (200 nm) element 13 Light- ITSODBT3P-II:MoOx PCBBi1BP ***** 9pPCCzPNfpr NBphen LiF Al emitting (70 nm)(2:1, 70 nm) (20 nm) (30 nm) (15 nm) (1 nm) (200 nm) element 14 Light-ITSO DBT3P-II:MoOx PCBBi1BP ****** 9pPCCzPNfpr-02 NBphen LiF Al emitting(70 nm) (2:1, 70 nm) (20 nm) (30 nm) (15 nm) (1 nm) (200 nm) element15 * 9PCCzNfpr:[Ir(dmpqn)₂(acac)] (1.0:0.1, 40 nm) **10PCCzNfpr:[Ir(dmpqn)₂(acac)] (1.0:0.1, 40 nm) ***9mPCCzPNfpr:[Ir(dmpqn)₂(acac)] (1.0:0.1, 40 nm) ****9mPCCzPNfpr-02:[Ir(dmpqn)₂(acac)] (1.0:0.1, 40 nm) *****9pPCCzPNfpr:[Ir(dmpqn)₂(acac)] (1.0:0.1, 40 nm) ******9pPCCzPNfpr-02:[Ir(dmpqn)₂(acac)] (1.0:0.1, 40 nm)

<<Operation Characteristics of Light-Emitting Elements>>

Operation characteristics of the fabricated light-emitting elements 10to 15 were measured. Note that the measurement was performed at roomtemperature (in an atmosphere kept at 25° C.).

FIG. 59, FIG. 60, FIG. 61, and FIG. 62 show the currentdensity-luminance characteristics, the voltage-luminancecharacteristics, the luminance-current efficiency characteristics, andthe voltage-current characteristics, respectively, of the light-emittingelements.

Table 17 shows initial values of main characteristics of thelight-emitting elements at around 1000 cd/m².

TABLE 17 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 3.6 0.25 6.2 (0.68,0.32) 1000 17 14 18 emitting element 10 Light- 4.6 0.32 8.0 (0.68, 0.32)940 12 8.0 14 emitting element 11 Light- 3.2 0.20 4.9 (0.68, 0.32) 93019 19 21 emitting element 12 Light- 4.0 0.33 8.4 (0.68, 0.32) 990 12 9.314 emitting element 13 Light- 3.3 0.27 6.8 (0.68, 0.32) 1100 16 15 19emitting element 14 Light- 3.3 0.29 7.2 (0.68, 0.32) 900 13 12 15emitting element 15

FIG. 63 shows emission spectra when current at a current density of 2.5mA/cm² was applied to the light-emitting elements. As shown in FIG. 63,the emission spectrum of each light-emitting element has a peak ataround 629 nm that is probably derived from light emission of[Ir(dmpqn)₂(acac)] contained in the light-emitting layer 913.

Next, reliability tests were performed on the light-emitting elements.FIG. 64 shows results of the reliability tests. In FIG. 64, the verticalaxis represents normalized luminance (%) with an initial luminance of100%, and the horizontal axis represents driving time (h) of theelements. As the reliability tests, constant current driving tests at aconstant current density of 75 mA/cm² were performed.

The results of the reliability tests show that the light-emittingelements 10 to 15 including 9PCCzNfpr, 10PCCzNfpr, 9mPCCzPNfpr,9mPCCzPNfpr-02, 9pPCCzPNfpr, and 9pPCCzPNfpr-02, respectively, which arethe organic compounds of embodiments of the present invention, in thelight-emitting layers have high reliability. This indicates that the useof the organic compound of one embodiment of the present invention iseffective in improving the reliability of a light-emitting element.

Example 22 Synthesis Example 15

This example describes a method for synthesizing10-[4-(9′-phenyl-3,3′-bi-9H-carbazol-9-yl)phenyl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 10mPCCzPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(158) in Embodiment 1. The structure of 10mPCCzPNfpr is shown below.

A synthesis method of 10mPCCzPNfpr is shown by synthesis schemes (o-1)to (o-4) below.

Example 23 Synthesis Example 16

This example describes a method for synthesizing11-[(3′-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9′,10′:4,5]furo[2,3-b]pyrazine(abbreviation: 11mDBtBPPnfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(178) in Embodiment 1. The structure of 11 mDBtBPPnfpr is shown below.

A synthesis method of 11mDBtBPPnfpr is shown by synthesis schemes (p-1)to (p-7) below.

Example 24 Synthesis Example 17

This example describes a method for synthesizing10-[3-(9′-phenyl-3,3′-bi-9H-carbazol-9-yl)phenyl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 10pPCCzPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(240) in Embodiment 1. The structure of 10pPCCzPNfpr is shown below.

A synthesis method of 10pPCCzPNfpr is shown by synthesis schemes (q-1)to (q-4) below.

Example 25 Synthesis Example 18

This example describes a method for synthesizing9-[3-(7H-dibenzo[c,g]carbazol-7-yl)phenyl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mcgDBCzPNfpr), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(242) in Embodiment 1. The structure of 9mcgDBCzPNfpr is shown below.

A synthesis method of 9mcgDBCzPNfpr is shown by synthesis schemes (r-1)to (r-4) below.

Example 26 Synthesis Example 19

This example describes a method for synthesizing9-{3′-[6-(biphenyl-3-yl)dibenzothiophen-4-yl]biphenyl-3-yl}naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mDBtBPNfpr-03), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(249) in Embodiment 1. The structure of 9mDBtBPNfpr-03 is shown below.

A synthesis method of 9mDBtBPNfpr-03 is shown by synthesis schemes (s-1)to (s-4) below.

Example 27 Synthesis Example 20

This example describes a method for synthesizing9-{3′-[6-(biphenyl-4-yl)dibenzothiophen-4-yl]biphenyl-3-yl}naphtho[1′,2′:4,5]furo[2,3-b]pyrazine(abbreviation: 9mDBtBPNfpr-04), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(250) in Embodiment 1. The structure of 9mDBtBPNfpr-04 is shown below.

A synthesis method of 9mDBtBPNfpr-04 is shown by synthesis schemes (t-1)to (t-4) below.

Example 28 Synthesis Example 21

This example describes a method for synthesizing11-[3′-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9′,10′:4,5]furo[2,3-b]pyrazine(abbreviation: 11mDBtBPPnfpr-02), which is the organic compound of oneembodiment of the present invention represented by Structural Formula(251) in Embodiment 1. The structure of 11mDBtBPPnfpr-02 is shown below.

A synthesis method of 11 mDBtBPPnfpr-02 is shown by synthesis schemes(u-1) to (u-7) below.

Example 29

In this example, a light-emitting element 16 (light-emitting element ofone embodiment of the present invention) was fabricated using12mDBtBPPnfpr (Structural Formula (208), Example 11) in itslight-emitting layer and a comparative light-emitting element 17 wasfabricated using2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline(abbreviation: 2mDBTBPDBq-II) in its light-emitting layer. The measuredcharacteristic results of these light-emitting elements will bedescribed below.

The element structures of the light-emitting element 16 and thecomparative light-emitting element 17 fabricated in this example weresimilar to the element structure described in Example 2 with referenceto FIG. 11. Table 18 shows specific structures of layers in the elementstructures. Chemical formulae of materials used in this example areshown below.

TABLE 18 Hole- Light- Electron- First Hole-injection transport emittinginjection Second electrode layer layer layer Electron-transport layerlayer electrode 901 911 912 913 914 915 903 Light- ITSO DBT3P-II:MoOxPCBBiF * 12mDBtBPPnfpr NBphen LiF Al emitting (70 nm) (2:1, 60 nm) (20nm) (25 nm) (15 nm) (1 nm) (200 nm) element 16 Comparative ITSODBT3P-II:MoOx PCBBiF ** 2mDBTBPDBq-II NBphen LiF Al light-emitting (70nm) (2:1, 60 nm) (20 nm) (25 nm) (15 nm) (1 nm) (200 nm) element 17 *12mDBtBPPnfpr:PCBBiF:[Ir(dppm)₂(acac)] (0.75:0.25:0.075, 40 nm) **2mDBTBPDBq-II:PCBBiF:[Ir(dppm)₂(acac)] (0.75:0.25:0.075, 40 nm)

<<Operation Characteristics of Light-Emitting Elements>>

Operation characteristics of the fabricated light-emitting element 16and comparative light-emitting element 17 were measured. Note that themeasurement was performed at room temperature (in an atmosphere kept at25° C.).

FIG. 65, FIG. 66, FIG. 67, and FIG. 68 show the currentdensity-luminance characteristics, the voltage-luminancecharacteristics, the luminance-current efficiency characteristics, andthe voltage-current characteristics, respectively, of the light-emittingelement 16 and the comparative light-emitting element 17.

Table 19 shows initial values of main characteristics of thelight-emitting element 16 and the comparative light-emitting element 17at around 1000 cd/m².

TABLE 19 External Current Current Power quantum Voltage Current densityChromaticity Luminance efficiency efficiency efficiency (V) (mA)(mA/cm²) (x, y) (cd/m²) (cd/A) (lm/W) (%) Light- 3.0 0.04 1.1 (0.56,0.44) 670 61 64 26 emitting element 16 Comparative 3.0 0.07 1.6 (0.56,0.43) 1100 67 70 28 light-emitting element 17

FIG. 69 shows emission spectra when current at a current density of 2.5mA/cm² was applied to the light-emitting elements. As shown in FIG. 69,the emission spectrum of each light-emitting element has a peak ataround 586 nm that is probably derived from light emission of[Ir(dppm)₂(acac)] contained in the light-emitting layer 913.

Next, reliability tests were performed on the light-emitting elements.FIG. 70 shows results of the reliability tests. In FIG. 70, the verticalaxis represents normalized luminance (%) with an initial luminance of100%, and the horizontal axis represents driving time (h) of theelements. As the reliability tests, constant current driving tests at aconstant current density of 75 mA/cm² were performed.

The results of the reliability tests show that the light-emittingelement 16 including 12mDBtBPPnfpr, which is the organic compound of oneembodiment of the present invention, has higher reliability than thecomparative light-emitting element 17 including 2mDBTBPDBq-II. This isprobably derived from a difference in molecular structures between12mDBtBPPnfpr and 2mDBTBPDBq-II, that is, a difference between aphenanthrofuropyrazine skeleton and a dibenzoquinoxaline skeleton, thusshowing robustness of a furopyrazine derivative of one embodiment of thepresent invention. Accordingly, it is indicated that the use of theorganic compound of one embodiment of the present invention is effectivein improving the reliability of a light-emitting element.

This application is based on Japanese Patent Application Serial No.2017-145790 filed with Japan Patent Office on Jul. 27, 2017 and JapanesePatent Application Serial No. 2017-231510 filed with Japan Patent Officeon Dec. 1, 2017, the entire contents of which are hereby incorporated byreference.

What is claimed is:
 1. An organic compound represented by GeneralFormula (G1):

wherein Q represents oxygen or sulfur, wherein Ar¹ represents asubstituted or unsubstituted condensed aromatic ring, wherein R¹ and R²independently represent hydrogen or a group having 1 to 100 total carbonatoms, and wherein at least one of R¹ and R² comprises a hole-transportskeleton.
 2. The organic compound according to claim 1, wherein Ar¹represents any one of substituted or unsubstituted naphthalene,substituted or unsubstituted phenanthrene, and substituted orunsubstituted chrysene.
 3. The organic compound according to claim 1,wherein Ar¹ in General Formula (G1) is any one of General Formulae (t1)to (t3):

wherein R³ to R²⁴ independently represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and a substituted or unsubstituted aryl group having 6 to 30carbon atoms, and wherein * represents a bonding portion in GeneralFormula (G1).
 4. The organic compound according to claim 1, whereinGeneral Formula (G1) is any one of General Formulae (G1-1) to (G1-4):

wherein R³ to R⁸ and R¹⁷ to R²⁴ independently represent any one ofhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 7 carbon atoms, and a substituted or unsubstituted aryl group having6 to 30 carbon atoms.
 5. The organic compound according to claim 1,wherein the hole-transport skeleton is any one of a substituted orunsubstituted diarylamino group, a substituted or unsubstitutedcondensed aromatic hydrocarbon ring, and a substituted or unsubstitutedπ-electron rich condensed heteroaromatic ring.
 6. A light-emittingelement comprising the organic compound according to claim
 1. 7. Alight-emitting element comprising an EL layer between a pair ofelectrodes, wherein the EL layer comprises the organic compoundaccording to claim
 1. 8. A light-emitting element comprising an EL layerbetween a pair of electrodes, wherein the EL layer comprises alight-emitting layer, and wherein the light-emitting layer comprises theorganic compound according to claim
 1. 9. An organic compoundrepresented by General Formula (G1):

wherein Q represents oxygen or sulfur, wherein Ar¹ represents asubstituted or unsubstituted condensed aromatic ring, wherein R¹ and R²independently represent hydrogen or a group having 1 to 100 total carbonatoms, and wherein at least one of R¹ and R² is a group comprising acondensed ring.
 10. The organic compound according to claim 9, whereinAr¹ represents any one of substituted or unsubstituted naphthalene,substituted or unsubstituted phenanthrene, and substituted orunsubstituted chrysene.
 11. The organic compound according to claim 9,wherein Ar¹ in General Formula (G1) is any one of General Formulae (t1)to (t3):

wherein R³ to R²⁴ independently represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and a substituted or unsubstituted aryl group having 6 to 30carbon atoms, and wherein * represents a bonding portion in GeneralFormula (G1).
 12. The organic compound according to claim 9, whereinGeneral Formula (G1) is any one of General Formulae (G1-1) to (G1-4):

wherein R³ to R⁸ and R¹⁷ to R²⁴ independently represent any one ofhydrogen, a substituted or unsubstituted alkyl group having 1 to 6carbon atoms, a substituted or unsubstituted cycloalkyl group having 3to 7 carbon atoms, and a substituted or unsubstituted aryl group having6 to 30 carbon atoms.
 13. The organic compound according to claim 9,wherein the condensed ring is any one of a substituted or unsubstitutedcondensed aromatic hydrocarbon ring and a substituted or unsubstitutedπ-electron rich condensed heteroaromatic ring.
 14. The organic compoundaccording to claim 9, wherein the condensed ring is a substituted orunsubstituted condensed heteroaromatic ring comprising any one of adibenzothiophene skeleton, a dibenzofuran skeleton, and a carbazoleskeleton.
 15. The organic compound according to claim 9, wherein thecondensed ring is a substituted or unsubstituted condensed aromatichydrocarbon ring comprising any one of a naphthalene skeleton, afluorene skeleton, a triphenylene skeleton, and a phenanthrene skeleton.16. The organic compound according to claim 9, the organic compound isrepresented by any one of Structural Formulae (100), (123), (125),(126), (133), (156), (208), (238), (239), (244), (245), and (246).


17. A light-emitting element comprising the organic compound accordingto claim
 9. 18. A light-emitting element comprising an EL layer betweena pair of electrodes, wherein the EL layer comprises the organiccompound according to claim
 9. 19. A light-emitting element comprisingan EL layer between a pair of electrodes, wherein the EL layer comprisesa light-emitting layer, and wherein the light-emitting layer comprisesthe organic compound according to claim
 9. 20. An organic compoundrepresented by General Formula (G1):

wherein Q represents oxygen or sulfur, wherein Ar¹ represents asubstituted or unsubstituted condensed aromatic ring, wherein R¹ and R²independently represent hydrogen or a group having 1 to 100 total carbonatoms, wherein at least one of R¹ and R² comprises a hole-transportskeleton, wherein the at least one of R¹ and R² is a group representedby General Formula (u1):A¹-(α)_(n)-*  (u1) wherein α represents a substituted or unsubstitutedarylene group having 6 to 25 carbon atoms, wherein n represents aninteger of 0 to 4, and wherein A¹ represents a substituted orunsubstituted aryl group having 6 to 30 total carbon atoms or asubstituted or unsubstituted heteroaryl group having 3 to 30 totalcarbon atoms.
 21. The organic compound according to claim 20, wherein A¹in General Formula (u1) is any one of General Formulae (A¹-1) to(A¹-17):

wherein R^(A1) to R^(A11) independently represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and a substituted or unsubstituted aryl group having 6 to 30carbon atoms.
 22. The organic compound according to claim 20, wherein αin General Formula (u1) is any one of General Formulae (Ar-1) to(Ar-14):

wherein R^(B1) to R^(B14) independently represent any one of hydrogen, asubstituted or unsubstituted alkyl group having 1 to 6 carbon atoms, asubstituted or unsubstituted cycloalkyl group having 3 to 7 carbonatoms, and a substituted or unsubstituted aryl group having 6 to 30carbon atoms.
 23. A light-emitting element comprising the organiccompound according to claim
 20. 24. A light-emitting element comprisingan EL layer between a pair of electrodes, wherein the EL layer comprisesthe organic compound according to claim
 20. 25. A light-emitting elementcomprising an EL layer between a pair of electrodes, wherein the ELlayer comprises a light-emitting layer, and wherein the light-emittinglayer comprises the organic compound according to claim 20.